Its all about the hubs and the spokes, baby!
Most Hub cities seem kind of arbitrary and stupid when you think about them... are that many people really going to Detroit, or Pittsburgh, or Atlanta?
The answer...no! Relatively few people ever actually are going to a hub city when they are on a plane to one. If even half the people on every Delta flight through ATL actually got off in Atlanta, the city would be a zoo in minutes. But they don't, and that is the key. They are simpy going through to somewhere else. The airlines make their revenue by building a critical mass of people going to Topeka until it actually justifies buying a 727 and all that jet fuel.
Personally I think the Hub and Spoke system is the best invention in modern American history, though it can create huge problems, like ORD a couple of weeks ago.
Anyhoo, I think it is a great idea for USAir to establish a hub out there. They need a stronger presence in the west. USAir has really taken off in the last few years. I was afraid of them like everyone else after that Pittsburgh crash, but I flew them a couple times recently and they were superb, really great... so I am rooting for them to kick UAL and AA of their high horses. UAL and AA are so crappy to their customers it is amazing that they have such market dominance.