Isn't this making the assumption that the stuff that needs to get done is fixed size? New technologies also create entirely new categories of jobs.
"Computer" used to be a profession, where people would sit and do multiplication tables and arithmetic all day [1]. Then computing machines came along and put all those people out of work, but it also created entire new categories of jobs. We got software engineers, computer engineers, administrators, tons of sub-categories for all of those, and probably dozens more categories than I can think of.
I think that there's a very high likelihood with the current jobs that humans do better than computers, most will be replaced by cheaper AI labor. However, I don't see why we should assume that set of things that humans do better than computers is static.