The CBDs of many Sun Belt cities are more GOP-voting than their other urban neighborhoods. A lot of it is explained by racial demographics, but it's also the case that suits-in-a-glass-penthouse will skew more conservative than the kombucha-drinking gentrifiers who prefer more creative neighborhoods.
Austin isn't even the best place to see this. The main downtown precincts in Houston and Nashville voted for Romney!
Also the wealthy condo-dwellers in downtown Houston mostly still today work in the oil and gas industry. Nashville as the state capital is going to have a similar effect to Austin where Republican-oriented lobbyists and other workers related to the fact that the Republican-dominated state government is based there will live downtown near the capitol building.
Which is roughly the same point I was making earlier.