What obstructs 95% of chess players?

However, only a very small group of players (less than 5%) will experience any significant progress. The majority of players (95%) will unfortunately experience only slight advancement or, worse, no progress at all.

In reply to this obvious question, this 2nd group of players will start providing various lame excuses such as:

• “ I’m a good player, but only have problems with tactics (or opening repertoire or anything else)”.
• “I don’t want to memorise opening lines, because I like creativity.”
• “I have problems with concentration, and sometimes make blunders.”

I agree with this. I thought I was good when I was 2000, then gradually learned how much stuff I didn't know, and saw how many mistakes I was making. 

2000 is OK, nothing special, lots of room for big improvement. 

The truth is that there's huge room for improvement for the vast majority of players, and that's the bottom line. 

Also, this sounds a lot like Smirnov, who I really admire, because his courses helped me gain a lot of rating points. 

Pretty good advice. Basically if you want to improve, you have to change the way you play, and learn new things.

Change is sometimes psychologically hard though. We want to continue doing things our way.

If you are objectively looking at your situation, the better you get the more you realize how much more there is that you don't know.  And that applies to most things of complexity.

When I graduated from high school, I thought I knew 90% of all there was to know about chemistry, which I had chosen as my profession at age 12.  When I received my graduate degree in chemistry from IIT and in a few years was chief chemist of process development research for a subsidiary of Dow Chemical, I realized I didn't know 10% of chemistry.

When I began to study piano in my 50's, I thought I'd be excellent within 3 years.  My logo shows me playing Chopin in a major college adult recital that I qualified for after 7 years of basic and performance lessons, theory classes, improvization seminars. etc.  I'm still, at 66, not an ace by any means!

i am the worst player above 2100 

I now realize that when I was seriously studying chess many years ago, I made three major mistakes that kept me from making much progress.

1. Studying the wrong things. I spent endless hours memorizing opening lines, instead of a mix of openings, tactics, strategy, and endgames. I spent some time on the other areas, but more than 75% of my study time was on openings.

2. Studying superficially. You can't just play over games or positions: they need to be studied and understood in order to really learn from them. Studying chess is hard work. It's not passive absorption. I didn't realize that back then.

3. Failing to focus on the most vital aspect of playing strong chess: analysis. The better you are at analyzing concrete variations, the better you are at chess. Understanding strategy guides you in deciding what variations to analyze, and mastering tactics is essential in carrying out the analysis, but in the end you must improve your analytical skills if you want to be a better chess player.

I liked the way IM Bartholomew put it on his Youtube channel. Improvement often happens in leaps, not gradually. For example, you study material for a few months, not seeing a visible improvement, then - boom! - at some point you start suddenly playing much better. The knowledge you accumulate needs some time for your brain to process and put in your repertoire.

For me, this was the biggest reason I gave up on playing chess seriously in around 2007. Having a rating of 2200 on daily chess websites, I simply didn't feel like anything I studied made much difference; I knew there was a huge room for improvement, but I just didn't know how the improvement worked. I got frustrated and gave up on regular chess for a looooong time.

Recently hopped in back to playing, and suddenly I feel that I understand the positional play much better than before! Even in that idle time, I guess, my brain was working on all that information passively, and now that I am back in action, I am able to use that information.

So, I think, this effect is what holds a lot of players. You are much less inclined to put in an effort in something if you don't see the immediate result. Our desire for instant gratification makes long studies with seemingly little effect hard to commit to. If you do commit, and accept that the improvement might not be noticeable in a while, but believe that you are not wasting your time and keep going - then you are very likely to be rewarded in the end.

For many, my self included, improvement is not really an objective.

When I started chess at age 19, I was USCF 1450. Now I am I am 1650. Not much of a budge, but I HAVE ENJOYED reading about chess, playing and learning for 30 years.

Some of us, perhaps most of us,  just consider it a game to play and study. We do not all care about "improving". It is a game.