And it isn't just the U.S. - a number of other countries with representative governments show this pattern.
My thoughts exactly.
"urban collectivism versus rural individualism"
I'll take this one. I've lived both places - and it was quite an adjustment to realize that the government didn't have to provide everything for me - garbage collection, police protection, schooling etc.
Then I learned I could do it better. And keep my taxes lower, and keep some semblence of privacy from the government over my life.
People in the NE are TAUGHT to rely on the government. The idea of taking charge for themselves is alien. It's a culture thing. They need to experience it to realize the superiority of individualism.