It turns out that with enough effort, "chess" can be lumped in with "arithmetic". The machines are just better at it. We're continually finding new things in that category, including things we never would have guessed. But that doesn't mean that everything is. At least right now, very little is.
Even things that AI has gotten best at, like coding, are nowhere near that category yet. AI-written text and code is still crap compared to what humans can write. Both can often superficially look better, but the closer you look and the less a human guided it, the worse you discover it is.
I suspect you are comparing AI output to the best human output?
Chess bots could beat the vast majority of humans at their game long before they could beat the world champion.
Similarly, AI generated code and text and images etc are getting more and more competitive with what regular humans can produce. Especially if you take speed and cost into account.
Even things that AI has gotten best at, like coding, are nowhere near that category yet. AI-written text and code is still crap compared to what humans can write. Both can often superficially look better, but the closer you look and the less a human guided it, the worse you discover it is.