In my limited experience outside of one of those hubs I can say that's definitely a factor. I've spoken to a few good candidates that when decision time came got cold feet because of fear that the local ecosystem not being strong enough to provide a security cushion in case something went poorly.

This is what ultimately led to my moving to the Bay Area despite the pay increase not being even close to the cost of living increase. In Nowheresville, USA, a job change usually means moving to a different city. In the Bay Area and other tech hubs, you have a menu of options to choose from that don't involve picking up and moving your family.

That's interesting, never really thought of that way. I'll keep that in mind in my decision making process