There's plenty of reasons a job market wouldn't clear even if you raised the pay. You can't get blood from a stone, sort of thing.

For instance, American citizens are not going to become farmworkers even if you paid them FAANG engineer wages. They just aren't.

I think to attract people to certain careers, anytime after they're born is too late. You have to have started with their parents. Good chess players are good because they started at age 5, not because they went to school for it.