[ghaff]

Doctors are just one example and there are many reasons why a doctor may choose to practice in, say, the Boston area than in some 20,000 person town in North Dakota--though you're right than, in many cases, medical professionals have a pretty wide choice in where they live and work depending upon how choosy they are.

But a ton of STEM jobs do require access to labs and other facilities or may have requirements related to security clearances etc. A lot of skilled people can't just work from home and many others travel a lot even if they don't regularly come into an office.