Can you really become a class A player by studying tactics?

I wouldn't say equally good in every department (Kasparov had amazing calculation and opening prep but was relatively weak in defense since he'd always play an active defense even in times when passive would be more appropriate) but rather meet a baseline in every category.  

We are the average of our skillsets not our best skill.  It's like running, you can run 13 miles an hour for part of a 5k, but when you cross the finish line your time is an average.  The same is with chess.  You can have expert level tactics where you can solve tactical tasks as well as an expert, but if your positional understanding, endgames, opening understanding, and technique are 1000 strength you'd be a novice, the tactical skills would be invisible since you wouldn't have the chance to use them often.  

Sure but even the pieces don't just fall off then you still have to deal with complex calculations. I don't mean to downplay the rating at all. I only think that tactics don't really stop being an important issue even for higher rated players. I like to post this game in particular when talking about such things. It was eye-opening for me anyway. 

http://chesstempo.com/gamedb/game/1245024/ply/

At the lower class levels, the great majority of games are decided by tactical errors, often very simple ones. Developing strong tactical vision will also help you become a better positional player because you will be familiar with certain tactical patterns and can look to get to those positions where you have the favorable tactical chances. Conversely, you will learn to avoid positions where opponents are able to use certain tactical patterns against you. No, this is not master-level play, but below 1800 you can win a ton of games just with better tactical vision.

I can assure you that I became a Class A player because I studied tactics, and also took lessons from a master, and studied endgames, and spent a lot of time developing as a positional player, and ...

Yes, you can.  I played a lot of Fischer games.  Problem is, I developed a lot of bad habits, like time trouble looking for great combinations.  Also, my opening is pretty weak and it keeps me from getting expert OTB.  I play too sharp not to have my openings down.  So, I seem to win against all B and below just based on seeing the board better, am about 35% against A, and am abysmal against experts and masters. I have one master win and just a handful of expert wins and draws.  Probably too late for me, but I would encourage you to spend a lot of time on opening repetoire along with tactics.  And if you are a tactical player, don't choose positional openings and defenses.

It sounds as if the original question should have been "Can you really become a Class A player by only studying tactics?" The answer to that question is almost certaily no.

I had a similar reaction to the title question, though from a different angle.

It takes a fair amount of effort to make A. Obviously not as much as Expert or Master, but still you don't make A without some real work. I can't imagine anyone that motivated who wouldn't study more than tactics.

Even De La Maza who claimed that obsessing over tactics for several hours a day was the key to his 400 point rating increase in a year, admitted he had read Silman and other books before embarking on his tactics program.

lol

Fischer, like Capa, preferred crystal-clear positional play over random tactical positions. Of course he knew how to attack. Of course he was excellent at calculating. But his best games are marked by a great positional sense rather than sheer tactical brutality. Every world champion, including Tal, had excellent positional sense. They all studied openings. They all excelled in the endgame. Mihail Marin even wrote a book that included Tal's brilliant endgame play. While the world champions varied in how they solved problems, they all studied the basics. 

If you're studying complete games of the greats from the past, you aren't just focusing on tactics.

Fischer said, "tactics flow from a superior position."

Swindles flow from a desperate position. I said that.

Was that really a Fischer original? Steinitz and Tarrasch said similar things.

But you'd better have your tactics handy in a superior position, or else it may become an equal position.

Of course not.

Here's a quote I love:

I can comprehend Alekhine's combinations well enough; but where he gets his attacking chances from and how he infuses such life into the very opening -- that is beyond me. Give me the positions he obtains, and I should seldom falter.

--Rudolph Spielmann

mostly in the opening i find that good development and space creation for your own pieces to move creates fantastic tactical opportunities later. Positional chess should be played when there does not seem to be a tactical alternative or early in the game when you need to think long term.

Fischer studied Morphy.  If you look at his exhibition games, you will find a lot of Evan's Gambits and King's Gambits.

Really?

Evan's is refuted? Nakamura - Anand, 2014 was draw