Intersting topic...
I had and have those crisis time and again. I am (or better was) quite good in correspondence chess (at best over 2300). My feeling is, that my chess abilities and knowledge are significantly better than what I produce over the board (1950 DWZ nearly 2000 Elo). My practical experience is too limited and I'm lacking gears to shift up my concentration in the desirable ways. In more than one of my latest games I blundered pawns (or even kings

) after decent and even skillful play.
All to often I asked myself "What the hell am I doing here?" Toying with wooden or plastic pieces. It is like achieving nothing even if you achieve something (a full point, a hard fought half point). What disappointed me quite often was that I only won after the opponent's mistakes - and it was quite often easy to detect them; mostly not more than two- or three-movers. At much lower stage the Alekhine-phenomenon - the former WC disliked it, when his opponents lost without fight and beauty.
The sad truth is: Successful perfection isn't possible in chess. You need those devaluating mistakes...
That's the difference to art - painting, drawing, making music, acting. In chess you battle your opponent. And he only disturbs (til you loose).
I haven't played more then say five games that really satisfied me. Even if I take the deep CC-games into account. That's a meager cut.
And from time to time I get bored with this cut. It is a enormeous waste of time. So many books wait to be read and I stumble chess. Aargh.
On the other hand: It is big fun to work on analysis. To brush up an underestimated opening variation, to save a bad ending.

Which offers the connection to correspondence chess.
But actually the crisis has reached my area of relative excellence. CC (and what is remarkable: it doesn't touch me... Never knew that before). For the first time since, well ever, I was smashed to the floor with a significant minus in two tournaments. I never got infected with the analyisis-virus and so dropped one game after the other, believe it or not: even on time.

I don't know why. I wasn't caught by the games.
I don't want to blame computer usage on every side. That's normal and I had no problem with it earlier on.
But infact now I'm bored with the modern CC. It is very sterile. Creativity is possible, but it hides between secret sidelines. And that requires too much devotion.
And on the other hand I'm not satisfied with over the board play - much to far away from halfway perfection, not enough reflection time.
Right now I'm teaching the aspiring youth of my club. They are very interested. You can infect them with gambit play to get things going, to get some joy of attacking play. Under this circumstances I know that chess is quite useful for concentration, planing, learning etc.
But for me it is not clear what chess is really good for. It is food for thought, yes, but what is that good for? Sudoku isn't bad either, and no one disturbs you

.
Perhaps gardening is best, at least it is thought for food.
And when all seems too depressing I think: "What about digging deepest? What is life for?" We don't know. Ah, it resembles chess in some way: Avoiding mate as long as possible
motörhead