There are a few exceptions to this, and they would include Atlanta (where it's literally flip-flopped - probably helps that the pro sports scene is so ass), Ohio, (where people tend to care more about the Buckeyes than just about anything else), and Michigan - specifically Michigan football and State basketball, but generally I agree. All these years later I still laugh at people who still seriously think bringing Rutgers into the Big 10 gave them the NYC market. It didn't, no matter how much everyone wants to pretend it did.
Seriously, though - why is the SEC so freaking historically popular? Because of the lack of professional sports outside of Atlanta - it's all they ever had.