I think you're mixing up different things. You're correct that teams "blue" and "red" are actually coalitions of people who believe quite different things. But in part that's because of geographic and cultural commonalities that cut across party lines. Both Oregon Democrats and Oregon Republicans skew libertarian, because the state does. In Georgia, both Democrats and Republicans skew more religious.

A lot of the intractability of our national politics is because geographical and cultural differences are overlaid on top of normal political differences. Splitting the country up along geographic lines would allow us to just fight over politics, instead of over deep-rooted cultural patterns.