Chess engines overtook human chess players more than a decade or two ago and human chess is thriving. Activities don't become less rewarding for you simply because someone else is better at it, even if that's a machine. A robotic arm can probably lift more than I do, doesn't take my enjoyment from working out away. And people enjoy the human aspect and narrative in any activity in its own right.

And that's the worst case in a way, because a chess computer is a really stupid machine. Getting beaten by minimax is kind of annoying. AGIs on the other hand if they ever exist will be very fascinating entities indeed and I wouldn't mind if they're better at anything than I am. And the same goes for scientific research. I haven't stopped doing math because Terence Tao is better than I'll ever be. How many people can seriously claim to be at the frontiers of science? The value in learning isn't in being the best guy or girl there is.