Spurs are working with San Antonio for a new arena downtown. The vision renders are pretty amazing, to be honest, and it would be awesome to have them right in the center of it all again. Frost never made sense to me with its location, but it was probably due to cost.
Austin may get MLB or NHL at some point, but I don't see them getting NBA due to proximity with the Spurs....but who knows. If I were a betting man, I'd see NFL going to San Antonio over Austin....but who knows. I hear that the little town of Hammond, Indiana, is getting the Bears, so...
It would be hard for me to cheer for anyone other than the Cowboys in the NFL, Rangers in MLB, and Stars in NHL....but NBA goes to the Spurs for me.

I enjoyed FC Dallas (formerly Dallas Burn), but Austin FC was an easy switch for a local team. The other sports wouldn't be as easy to switch allegiances.
In a lot of ways, I prefer minor league games to majors most of the time if I'm going in person. Cost is the main factor there, especially so it can be a family outing. I'd have to take out a second mortgage to regularly go to pro games these days with the whole family. I thoroughly enjoy pro games and watch many from the comfort of my own couch or at a sports bar with friends.