On the physician side, there's definitely big changes coming, and I'm banking on a move to up-front APPs and a few remote physicians overseeing things. But I'm actually also seeing a number of entities that hired a bunch of APPs and are now moving back to physicians only and saving money doing do (think urgent care, ED, inpatient), though some specialties work very efficiently with a primary APP or co-management model, particularly the procedural ones.
Why? As you said, hospitals have a hard time finding nurses (undersupply), so more nurses would be better for patients and hospitals. An influx of more nurses could ease the undersupply, but I don't see why it would necessary overcome it completely and even lead to the impeding oversupply.