Unfortunately people are gonna have to relocate and/or retrain in another field. It's a PITA but sometimes you've gotta do it. Survival.
The problem is that this is much, much easier said than done. What if you are upside down on your home and it would cost you money to unload it? It's also difficult to move to a strange place without already having a job lined up where you don't know anyone, especially if you are unemployed and don't have any money.
As for retraining--retrain, reeducate--for what? What if you aren't physically able to work as a nurse? What if you're concerned that after you've retrained and reeducated you'll face massive age discrimination and discrimination against the unemployed (meaning that you've just wasted a lot of time and money retraining)?
It's easy to say what you've said, but not as easy to do when you start contemplating the practical aspects of it.
Right now millions of people are going to college to retrain and reeducate for various fields and they are going to discover that (surprise) there just aren't enough jobs available for people in the fields they have just trained for. Ironically, people probably retrain for fields other people are trying to leave through retraining.
We have 5 or 6 people who need work for every 1 available job. There's just no way around that. All of the retraining, reeducating, and relocating in the world will not fix the nation's economy and job market.