Regionalism remains strong in the southeast and in Texas. Strong cultures each. The rest of the country, not so much. I've been interested during the 35 years since I graduated from UIUC how those I know (from school and otherwise) who migrate from the Midwest, Northeast or, increasingly over the past 20 years, California to those strong-culture regions adopt in general, and quite happily, the prevailing culture. Americans who emigrate regionally are extremely adaptable in that way. I have a former colleague form 25 years ago who ended up via mergers in Phoenix around 2005. He and his wife were hard core DC/NYC natives who didn't want to move. They embraced the Valley of the Sun and have no desire at this point to leave, though their kids are grown.
As I've grown older I've come full circle back to my Midwest roots, though I left for good in 1990. Whenever someone asks where I'm from I say "Ohio and Illinois." Those are the places that formed me. They're indelibly who I am. Everywhere subsequently has been a residence. Perhaps I'd feel differently if I'd moved to Texas or Atlanta.