I agree with your premise but the chess analogy falls flat.
We might, legitimately, see an enormous dropoff in people creating original works of literary, musical, and visual art (without AI).
If those motivated purely by money stop creating little of value will be lost
Great art - especially in modern times when that art involves expensive education (which if you're American must be paid for with interest) and the incorporation of technology and equipment - takes time and effort. If that time and effort cannot be paid for, then no matter how passionate an artist may be, unless they have sufficient personal wealth, that art must suffer.
Even the great artists of old needed patrons, because they needed to eat like anyone else. Michaelangelo didn't paint the Sistene Chapel ceiling for the love of the game, nor would he have.
I guarantee you that the working artists who have already lost commissions and work due to AI care about their craft.
People didn't stop painting because photography exists, they created new forms of photography. People didn't stop writing music or using new / unique instruments when synths and programs came along.
I genuinely believe that people will keep creating, it's in our nature, and we also like things made by other humans, because we can relate to them.
Creation should happen for whatever reason its creator becomes inspired with. The only absolute I can think of is no one should actually categorize worthy and unworthy motifs.
The only invalid reason is because you need to feed yourself, and the fact that we need to do that, we need to pay artists and everyone else just to survive, shows our failure as broader society.
