Has the decline of knowledge work begun?

At least for the moment, AI still needs knowledge workers to spec and prompt and check. AI makes knowledge workers more productive, but it doesn't eliminate the need for them.

And if knowledge workers are more productive, then knowledge work is cheaper. Cheaper knowledge work increases demand for knowledge work. So the number of workers required might actually increase. It also might not, but first order analysis that assumes decreased knowledge workers is not sufficient.

C.f. garment makers. Partial automation of clothes making made clothes cheaper, so now people have closets full of hundreds of garments rather than the 2 sets our great-grandparents likely had. There are now more people making garments now than there was 100 years ago.