[anonporridge]

Pure speculation, but if I had to hazard a guess, it's because the job is becoming increasingly inhumane.

More and more, nurses have to act like robots to remain in compliance, and that's not what any of them signed up for, and the increasing lack of intangible reward that comes from caring for people and creating a human connection, means they demand more explicit monetary reward for temporarily suppressing their humanity to do the job.