Looking closely at the map, I see that I lived the bulk of my life in one of the dense red clusters. I never saw it that way, though I did leave for better weather and more natural beauty. I could have lived out my life in the heartland and been happy (I'm writing this from that area right now.) Still, at old Megacorp, we could NOT keep transplants. I can't recall a single transplanted person saying how much they liked anything other than their j*b (if that). Our turnover was incredible - even though Megacorp had a reputation as a decent employer. We attempted to address the issues (lack of a "gene" pool for singles, lack of entertainment, lack of hiking, biking, boating, etc. etc.) Not much could be done though I give Megacorp credit for trying (creating their own nature preserves for hiking, giving free tickets to events, supporting community projects and getting folks involved - e.g., Habitat, etc. - supporting cultural events, etc. etc. I never saw the problems, myself, but listening to transplants complain about "nothing to do", I could see their point of view.
Now I live in a major blue dot (and BLUE state as well!). The only complaints I hear are economic and traffic. Anyone who can't find something to do is seriously mobility-challenged or just lazy. So maybe that's a part of what the study is finding, even if it isn't specifically addressed. YMMV