> There's not one example of a regional sports league that has had any sort of success in recent memory.

Er, we're talking about them right now. College sports are extremely regional but still have significant national appeal. Many, many people tune into SEC conference games who have no connection to the SEC.

If you think people wouldn't watch an SEC-only league (I'm using the SEC here because it's the most obvious example), then I think that betrays your knowledge of college sports.