> even when AI chess engines can easily defeat grandmasters, the human-AI combination still produces superior results to the AI alone.
Is this still the case? I didn't find a conclusive answer, but intuitively it's hard to believe. With limitless resources, AI can perform exhaustive search and is thus not possible to lose. Even with resource limits, something like AlphaZero can be very strong. Would AlphaZero+human beat pure AlphaZero?
With the weaker engines that run on browsers, you'll still catch cases where GMs have a good understanding of the position, and it takes the engine some time before the engine's understanding catches up. -- e.g. the GM will be explaining "this position is good", but the computer eval shows +1 before then climbing to +5 after some time.
Similarly, I recall a popular technique in videos where GMs play cheaters is for the GM to then adopt a solid, defensive structure. The engines then just shuffle pieces around. (Again, I suspect that's with the weaker engines running on the computer).
Though, some of the "engine vs engine" games I've seen have involved wild and inhuman play. -- In those cases, that's where I'd doubt humans would be of much help. I don't think AlphaZero+human would beat standalone AlphaZero.