They probably didn’t have that paradigm but we do: if there’s something humans could still do better, don’t we have the context to have thought of it?
We will have no idea what those new jobs will be, because they're in new sectors that are only now opening up. So when the internet replaced newspapers, those paper boys became Fortnite streamers, not ISP technicians. I could speculate, but even if I guess correctly it'll probably sound silly to us.
LLMs have terrible intelligence, creativity, and adaptability. But like most technology, they enhance human efficiency, they don't completely replace humans. The Jevons paradox tells us that increasing efficiency will increase total demand, not decrease it.