Just because it's been a thing for decades doesn't mean it instantly fixes demand in this case.
And the fact that a quick google search is showing new travel nurse jobs posted a week ago in new york, despite their curve dropping a couple months ago, is telling. It seems like they were unable to meet demand with that program.
The definition includes a vast set of un-credentialed workers; people at meat packing plants, grocery stores, cleaning staff, etc.
(Again, there will be licensed CNAs not working due to the cost of things like daycare. Raising wages changes that calculus, too.)