Yea that's true, it's a pretty overloaded word. From what I remember though, even the top players thought that there wasn't anywhere left to go with chess engines, before Alpha Zero basically ripped the roof off with a completely different play style back in 2017, beating Stockfish.

And the play style of Alpha Zero wasn't different in a way that needs a super trained chess intuition to see, it's outrageously different if you take a look at the games.

I guess my point is, that even if the current situation is basically a 'deadlock', it's been proven that it's not some sort of eternal knowledge of the game as of yet. There's still the possiblity that a new type of approach could blow the current top engines out of the water, with a completely different take on the game.

However, it is true that Elo gain on "balanced books" has stalled somewhat since Stockfish 16 in 2023, which is also reflected on the CCRL rating lists.

IMO AlphaZero was partially a result of the fact that using more compute also works. Stockfish 10 running on 4x as many CPUs would beat Stockfish 8 by a larger margin than AlphaZero did. To this day, nobody has determined what a "fair" GPU to CPU comparison is.