A lot of them are. And those that are are making $125-175K/year. It does mean relocating, or adding 1-2 hours commute on top off a 12 hour shift (that typically takes more like 14 hours once you add shift handoff and finishing paperwork that you don't have time to do during your shift because you have double the optimal patient load and half the CNA support...
>>why aren’t nurses quitting en masse to become traveling nurses?
because by definition, traveling nurse...travel. Yes you might get a gig for a while in your local hospital, but what happens when that ends? If you are young and/or single and don't own a house or locked into a 12-month lease, sure you can just pickup and move to the next place across the state or across the country - but if you are like most people, perhaps own a home, have a spouse with a local job and perhaps more importantly, kids in a local school system - it is very hard to just keep packing up and moving 2-3 times a year.