It looks like you're assuming there's no salary elasticity in the job market, which is probably not accurate. There are always trained nurses that maybe decided

It looks like you're assuming there's no salary elasticity in the job market, which is probably not accurate. There are always trained nurses that maybe decided to retire early, considered the stress not worth the pay and switched jobs, or something else like that. Higher pay can get them back on deck. Demand for nurses doesn't change abruptly and before importing people became a fad it was largely followed by supply.