I'm not sure I'm following, are you saying that SF feels bigger than Austin because of the surrounding metro area? I guess I'd assume that feeling is from population density (SF being 18.5k/sq mi vs 3k/sq mi in Austin), rather than the metro area. But maybe that's because I'm a new yorker that doesn't have a license, so cities to me are what I can get to on foot, which means the denser they are the more like a real city it feels to me.