Some sources of value and purpose in the current world that would be inconceivable to a hunter 20,000 years ago (prior to agriculture or written language):

1) Connecting directly with absent strangers via writing or photos or video 2) The beauty of finely crafted and intricate mathematical structures which unexpectedly cohere 3) The elegance of consilience, where a unified set of principles like natural selection or Newton's laws explain a vast set of phenomena 4) The pleasure of writing a software program and producing the intended output 5) The value of moral universalism -- improving the lives of people or other entities you have never met 6) Awe at the scope of the universe -- the stars are not lights in the sky, but inconceivably huge and distant objects

Now consider: "If AI is more capable than humans, there will be nothing of value for humans to do."

In a world where AI replaces humans at helping other people or discovering new ideas, we would lose many specific sources of value, including elements of the ones listed above. Other parts would remain: we can take pleasure in understanding relativity even if we did not discover it for ourselves.

But "The universe is no narrow thing." The idea that we won't discover new sources of value and purpose beyond what our meat brains can currently come up with is ludicrous parochialism.