The quality of the chess is only marginally lower, and in exchange you get more exciting games. Why is “going deeper into a position” something to be desired? Right now matches last 3-5 hours. Why not 8 hours? That’s deeper. Why not correspondence? That’s deeper still. Why not just watch Stockfish play Leela at depth 100? That’s way better than anything mere humans could do.
Chess has exploded in popularity because of the online revolution and faster, more exciting games that are still high quality.
And nothing will preclude anyone from playing classical chess, just make it a niche category for the old folks. As I said before, the WCC is already decided by rapid and blitz, since the classical section is usually drawn these days, so why even bother with a week’s worth of Sveshnikov draws? It’s pointless, tedious, ugly, and unwatchable.
Standard chess doesn't exist to satisfy crowds, but the challenge the players to do their best. Opening theory is a problem though, memorising a game up to move 20 is against the spirit of the game.960 chess or other variants are the future of chess.