
People who are more educated tend to be more left leaning. So if a region has good education, it tends to be less conservative. Areas that are doing well economically will attract more educated people and have a more diverse population, meaning more liberal. And if an area becomes more educated, it will usually be less conservative.
You also have the factor of conservative states just having shit governments. They just don’t want to fund anything. They don’t fund education, they do whatever the fuck Texas has done to fuck its own power grid, they don’t fund healthcare and social programs. This actively makes their own states worse.