I think this gets it a bit backwards. There has been a shortage of nurses for decades, and it’s getting worse. This is exacerbated by an aging population and restrictive immigration policies. Travel/agency nurses were supposed to be load balancers for a system with variable demand for labor, but for a variety of structural reasons agencies began to pay nurses more. This has prompted a landslide of nurses moving into agency work. Labor costs have risen accordingly, but fundamentally that’s driven by the shortage of supply. If you talk to administrators they will tell you that they hate relying on agencies but they have no viable alternatives. They can’t raise wages because they have little/no control over their own cost structure thanks to the screwed up way healthcare in the US works, and most hospitals are barely scraping by. There are no easy answers to this one, and blaming it on shortsighted administrators (of which there are many!) misses the larger context.