There are many former nurses who have the academic qualifications but have since left the profession. Some of those could be drawn back in with better pay and working conditions.
One of the main places nurses tend to go to leave the fray is the medical billing / "insurance" industry. Who else has extensive experience with ICD billing codes? So not only does the financial cancer strangle the people supplying actual healthcare, it shrinks the supply of them as well.
That's really not what happens. Most nurses doing clinical work aren't experts on the CPT and ICD-10 codes used in billing. Medical coders attend specialized courses to learn the detailed coding rules, and then pass a certification test. They get paid much less than an RN.
Some nurses do go to work for payers, mainly doing case reviews and utilization management. This is absolutely necessary to prevent waste, fraud, and abuse. Even in socialized medical systems they have people doing similar oversight work.
Sure, I agree the "insurance" industry employs people that aren't nurses, too.
The "oversight" function provided by "insurance" companies is terrible and hostile. It does nothing to stop every day waste, like rushed appointments, doctors telling you to come back in a few weeks for another billable event, repeated tests, etc. Meanwhile it creates administrative hoops based around rejustifying treatments that have already been justified by the front line doctors, to the point that many providers employ "nurse navigators" to wade through the hassle - care-providing potential is wasted on both sides of this pointless adversarial setup.