How much opening knowledge is needed for a 2000 rated (Fide Elo) player?

Sorry but I have to disagree. I mean the quote of Kasparov says nothing. He just said that all openings are playable but he did not say that you do not have to know your own opening. The most titled player advise to build a real opening repertoire when you reached a Fide Elo between 1800-2000+(for example GM Yussopow, IM Kostya etc.). I do not know how strong you are but there will be a strength in which opponents blunder less. A 2000 Fide rated player will not blunder that easy. You have to put him under pressure till he blunders. The fact is that you often have a worse position when you do not know the theory (especially in the sicilian).

depends heavily on what you play! some openings require a certain level of knowledge or else you will blow up OTB even at the club level.
They are certain ways to play where your requirement of deep knowledge is minimized.
Scotch, Rossolimo, exchange french and exchange caro. London system or other quirky systems, Some boring lines of the queen's gambit declined, Scandinavian (esp qd8 variation), philidor defense and the old-indian etc. Its harder to do with black but doable. These kinds of opening allow one to play "redneck chess" for far longer. With a basic understanding of each you can get playable openings.
So yeah, i think you can get by on little knowledge even at the 2000 FIDE level. but your choice of openings will be limited to accommodate the handicap.
Hello,
I want to reach 2000 Fide Elo and I know that tactics and endgames are very important and therefore I want to ask how much opening theory is needed.
I play e4:
Ruy lopez, Najdorf, Kan sicilian, Sveshnikov sicilian, Taimanov sicilian, Sicilian Dragon, Caro Kann, French defense, classical sicilian, Pirc Defense, Alekhine defense and Modern defense.
Against e4: Scotch, Berlin defense against Ruy lopez, Italian, Kings Gambit, Vienna etc.
Against d4: QGD
Against c4: e5
How much moves are required to be a solid 2000 Fide rated player? I know that this is different for each player but I want to know the "average case" according to stronger players.
For example I learned the Alekhine Defense (the exchange variation) as a white player and learned at least 12 moves in each variation. The problem is that there are often many systems and it is sometimes hard to memorise the correct move order.