Virtually impossible and literally impossible are two different things.
How good can I expect to become?

What's the latest start date for a modern GM anyway?
Staunton was 18 as I recall and Albin, going by one list that has some errors so don't take this for gospel, was 23. Older and lesser and more informal standards there though.
Why do you think there are only one thousand GM's out of 6 billion people? Do you think that absolutely anybody has the capacity to be in that 0.00000000000000000000001%?
I 'd say at least 50% of the world could become a grandmaster, but really, who wants to be a grandmaster at a young age? I'd say maybe 1 in 10 000 at most and then probably 3/4 of those would lose interest after a few years. Then once you are older, other comittments take away from being able to invest time with chess...

Why do you think there are only one thousand GM's out of 6 billion people? Do you think that absolutely anybody has the capacity to be in that 0.00000000000000000000001%?
I 'd say at least 50% of the world could become a grandmaster, but really, who wants to be a grandmaster at a young age? I'd say maybe 1 in 10 000 at most and then probably 3/4 of those would lose interest after a few years. Then once you are older, other comittments take away from being able to invest time with chess...
If they are pushed into chess by their parents from year one then maybe... If you mean 50% of the world could make a consciouse decision to become a GM and then reach that goal at a certain age (say before 20 years) you're just nuts.
Even players force fed chess from a very early age, with talent, don't always make it to GM. Sofia Polgar and Josh Waitzkin are examples.

I'll "sort of" AGREE with the AxBxC formula. However, I'd like to take it a step farther. I'd like to WEIGHT the letters. As it stands, each letter has equal weight, without regard to it's value. Also, I'd like to ADD the values instead of multiply them. Multiplying adds an excessive value. If I did 3 hours of work for BILL and 5 hours of work for SUE, you could NOT say I did 15 hours of work.
Letter A (time) is important, but it is a GIVEN. Humans improve at ANYTHING they do over time. I'd like to give A a 5% value.
Letter B (quality of study) is more important. Heck, I played hundreds of thousands of games over 35 years, most for "fun". I never had a tutor. I never gave it my all. It could be said that my study habits were POOR, thus my never being able to crack the 2000 mark. I had friends who had formal chess schooling whom I COULD NOT beat, and they played chess for far less time than I have . I'd like to put a 15% value on B.
Letter C is by far the MOST important of the 3. Talent, as we all know, cannot be taught or learned. It is a gift. Hard work alone cannot take you to the top of the PGA, for example. I'm sure there are many others who have hit more practice balls than Tiger Woods. I'm sure there are countless people who have logged thousand of miles in marathons who NEVER made it to the olympics. Talent and Genetics are synonymous, both are INNATE. Grow up to be 5'5" tall... kiss your dreams of being an NBA superstar goodbye. I'd like to give Letter C an 80% value.
So .05A + .15B + .8C = elo rating
In my RANDOM example, (.05) 10 x (.15) 5 x (.8) 2 = 2.85 NOT 17 or definitely not 100.
Remember, if all it took was hard work and studying to be great, everyone would be doing it. As JG27 said "not all brains are created equally for chess."

I would imagine there are a lot of IMs who have been striving for years, but don't quite reach the level they need to become GMs. Take IM Silman for example - I'm sure he would quite like to have become a GM, or IM John Watson. These guys show a really deep understanding in their writings, they have obviously spent many, many hours studying, researching, analysing, competing and writing, yet something is missing from their game to stop them reaching GM level.
To say that anyone or nearly anyone can reach GM level probably shows a misunderstanding of the level these guys are really playing at (and a certain lack of respect). It's one thing to study their games in retrospect, but quite another to come up with these moves time after time in competition, maintaining these high standards for the requisite number of years.

Add to the list IM John Donaldson. Two GM norms, hard worker, highest rating I can see is 2450.
Talented guy too who stood out clearly when he was a teen here in the NW.
Yet 1 norm short and apparently 50 rating points for GM status.
An old friend of Fischer's and well-known book seller Ken Smith FIDE 2365 would write in the back of his catalogs in his chess improvement essays, "As chess players we all come to a hill we cannot climb."
GM chess just isn't as easy as some seem to think. It's not just having knowledge and skill, you have to take those points away from the other guy too. Not easy.

I bet that an experienced teacher can sense where the trajectory of their students will end up.
I've put in a lot of time and effort and I have a nice shiny 2200+ FIDE rating to show for it; but there's nobody other than my own mother who thinks I'd be able to get to GM.
Talent plus a good work ethic will put you near the top of any profession/activity.

It's hard to answer the topic starter's question in general. Besides, all these "what if I do smth for years and years" questions never make any sense. If you REALLY like chess, you will be studying it no matter what. If not, then you will just forget about your life-long plan in a few months & find some other hobby.
I have spent a lot of time thinking about what is required for success in chess, have read numerous articles. Too much depends on the person, conditions, his interest for the game. Generally speaking, it's easier to learn chess when you're young: your cognitive abilities are better, you have more time, chess may be your main priority. On the opposite, it's quite hard to imagine a 35-year old person with a wife and two kids spending all his time studying chess & playing tourneys. That is possible in two reasonable cases: 1) he's a chess pro already 2) he loves chess very much and has a large fortune, so he can afford to do whatever he likes. For most people the situation is different. They find new occupations, get a job, etc. Therefore, the older you are the harder it is to progress, the less time you have left. However, it doesn't mean that you should feel doomed in chess - it's just a factor to be considered, nothing more.
Do you think that it's possible for an amateur (with a job and a family) to get passed 2200 or that is the upper bound one can reach while treating chess as a hobby?

Well, I feel that the average person if they work really hard and really well, it's quite possible to get to master strength (2200) but you have to be patient. Right now I feel tons of potential at getting there and have improved very rapidly up to 1700, but of course the higher you get the harder it is to improve. I appreciate every small rating jump I get now and in a matter of years it could add up. Beyond 2200, I have no idea, but don't count on it. If you're really serious about chess and younger then trying to become a regular master is a challenging but possible goal in the long term. To go beyond 2200 though, you have to start coming up with creative ideas sometimes that may go against what you learned at times to outplay your better opponents.
My high school buddy and I started playing each other at 13ish and going to a chess club together at somewhere around 15-16ish. We studied, we played, we did the same things. He is a 2400 rated IM, I got to 1913 USCF.
As in virtually any activity, all are not created equal. Sorry if this dissappoints. If you want to believe he just worked harder, that is fine, but its simply not true. Sure, there can a point in time when I moved on to other things and he did not, but by that point he was already nearing master rank. Prior to that point, I not only worked as hard as he did, but we generally worked on the same things at the same times in the same ways.

I'm happy that I sparked such a lively conversation. I want to make it clear that I'm no fool and of course I know that it depends on more than time, but the other variables aren't as tangible and can't be calculated. I'm just asking the question for the sake of conversation. It seems to of worked.
If I do have to estimate your playing strength at 40 - considering you're 19 now - I would say somewhere between 1800 and 2200.
Thank you for indulging in my question. I'll be aiming for that mark.
My high school buddy and I started playing each other at 13ish and going to a chess club together at somewhere around 15-16ish. We studied, we played, we did the same things. He is a 2400 rated IM, I got to 1913 USCF.
I don't believe that you are 1900 USCF and here you are rated 1200 in blitz. I looked at one of your games ... no 1900 player would ever move his bishop twice in the opening, while there are plenty of other developing moves.

N.B. this guy is rated 979 on chess.com.
there is hundreds of thousands of people on this site alone and almost all are better than you.
you will need a lot of work son.
i think you need to get off the forums, stop speculating and step your game up.
my rating is not so hot either, but i don't care.
who cares what you will be rated at 40? enjoy chess!

I'd just like to become that guy in the city park that dominates all the other players. I'd also like to beat the casual chess player about 95 percent of the time. I know that this requires work, and not just fantasizing, but I'm curious about the nature of chess's learning curve, and the difference between a 1700 player and a 1200 player. Could one of you give me some detail.
I don't think you would have to be Judit Polgar to accomplish that. Depending on what city park you play at, a strong class A to expert (1900-2100) is pretty much going to rule the roost outside of formal tournaments in bigger cities. That is a level that is certainly acheivable with a lot of tactics training, learning 5-6 openings really well, memorizing a 100 or so basic positions, and knowing how to play the more common endgames like a robot. That is acheivable in 1,000 hours (about an hour a day for 3 years) if you really want it.
You also have to spend a lot of time playing at that park and working your way up, no ammount of training by yourself is going to get you to class A, you need to overcome challenges at the board with real people and real pieces. For a mortal, USCF Expert is probably a realistic limit, much beyond 2000 requires an exponential increase in work - because to get beyond class A - expert, you are going to have to start BEATING other experts.
My high school buddy and I started playing each other at 13ish and going to a chess club together at somewhere around 15-16ish. We studied, we played, we did the same things. He is a 2400 rated IM, I got to 1913 USCF.
I don't believe that you are 1900 USCF and here you are rated 1200 in blitz. I looked at one of your games ... no 1900 player would ever move his bishop twice in the opening, while there are plenty of other developing moves.
Jeez dude, did you look at my standard games before calling me a liar? I have played like what, 4 or 5 blitz games here? But you wouldnt know that, having decided to call me a liar after looking at a grand total of one of them. PM me and I'll send you my real name from my gmail account with my name on it, you can look me up on uscf and applogize.
I'm about 1375 on FICS currently (1500 high) under my real name, with thousands of blitz games, and on Chesstempo.Com under the same name as here, ArtNJ, I am rated 1790 at their tactics problems, 1840 high, but only 1690 at blitz problems. While FICS blitz ratings are definitely lowish, its certainly always been clear to me that I suck at blitz and have never been anywhere near as good as I am at standard time control.
Anyway, useless digression caused by you calling me a liar for no reason.
Why do you think there are only one thousand GM's out of 6 billion people? Do you think that absolutely anybody has the capacity to be in that 0.00000000000000000000001%?
I think you'll find what I said more reasonable when you read it in its context, namely as a reply to the original poster having heard that "it's virtually impossible to become a grandmaster if you don't start when you very young".
And that's likely close to the truth. It's like being an athlete. You don't just pick up Football when you're 19 and then end up playing for Spain in the world cup.
I agree that "you don't just" do that, but it is very far from "virtually impossible". You know, I trained with GM Visser for some time. He became a GM at 42.