High property prices combined with stagnant wages drove the middle class out of cities. The high property prices resulted from the fact that our most successful businesses need to retain talent. And that talent base is much more liberal than the population at large.

Its not about liberal policies...its about the ability to afford a home. Even in Houston, wide parts of the central core are becoming completely unaffordable for families.

If anything, the liberal cities have become too successful in attracting high priced talent. Because the conservative areas aren't really competing for those good jobs.

If you have a choice....why live in Stockton when you can live in San Fran? Why live in Montgomery when you can live in Houston?

You don't see a lot of leading companies and industries locating in conservative areas. There's a reason for that. Because if you don't welcome immigrants, LGBT persons, single people, and non-Christians as equals in your communities (and provide them with amenities that they want), the businesses that need their talent won't go there. Now you could argue that the middle class people that are pushed out would simply form their own businesses that leverage their talent, but that hasn't largely happened. Because the middle class doesn't have access to capital like the upper class does. And that is the result of Conservative policies, which continue to concentrate wealth in the 'city class' hands. And Trump's new tax plan...is more of the same. Basically, you want to build a large or leading business...you'll probably be doing it in a city.

And there's another dynamic that might be at work here too. Corporate America tends towards those that have decided to prioritize their careers over family. Part of the middle class move is really just people who have decided to emphasize family over career. They tend to be less successful in the corporate world precisely because they put their families first. The Dems at least try to put some regulation in place to handle that (such as Family leave policies, equal pay for women, etc.) to try to sort that out.