I'm a French Defense player. As Peter Svidler opined in his interview on Chess24, "If the white player would prefer a quiet life he will find it harder to find a quiet life in the French than in the Spanish [Ruy Lopez]".
The main reason it isn't played is that it is harder for Black to play the French Defense than it is for White to play against it. He accepts the following limitations:
- He is facing a White pawn at e5 for much of the game in many of the variations
- As a result, his king's knight rarely gets to sit comfortably on f6
- As a result, White's queen often goes raiding on the kingside
- As a result, Black often can't castle safely on the kingside.
These are not problems that most players are comfortable having.
But I play it because:
- It's relatively easy to get the game into areas where I'm better prepared (and in more familiary territory) than White, which is unnerving to a lot of players of White
- It's a fighting defence, with a few traps, clever stratagems, and ways to knock White into burning a lot of time on his clock
- It shows you have nerve, and and that you have probably put a fair amount of effort into learning how to play a defence that can be tricky to handle. This can be intimidating by itself.
Obviously, at the GM and Super-GM levels, the players stay pretty booked-up, and you have to be really adventurous to suprise them (think Sveshnikov/Pelikan Sicilian, Scotch Game, King's Gambit, and so on, which were considered either unplayable or too quiet to be useful when they resurfaced in the latter half of the last century, typically with great success). Many of these players are now starting to try unorthodox ideas in the older established openings, like the Italian Game (Giuoco Piano). The French may get another day in the sun.
In the meantime, it is getting played by the likes of Carlsen, Caruana, Nakamura, Anand, Radjabov, Morozevich, Ivanchuk, So, Giri, Karpov, Grischuk, Harikrishna, Gelfand, Leko, Mamedyarov, Topalov, Wang Hao, Ponomariov and others.
So, while it's not getting played as much as the Spanish and Sicilian by the highest-level players, they certainly are playing it from time to time, even in blitz!