Sure, here's a direct answer:

Even after the mechanical loom was created, figuring out the next most important problem to work on was a job that humans did.

Unless you believe there's some hard limit on AI intelligence that will constrain it below the intelligence of a particular earthbound hairless ape, then eventually AI will be perfectly sufficient and probably better at figuring out the next most important problem to work on.

Ta-da, humans are completely removed from the value chain. Neither the loom nor the tractor could not do such a thing.