The landing fees are probably too high, plus you have Frontier, and other low cost carriers in Denver. Since there are other markets that Southwest could be the only low cost carrier, say Allentown, PA and Des Moines, IA, why should they go into Denver where they would have a LOT of competition?

There are also cities courting Southwest trying to get them into their airport. I don't think Denver has shown any interest, and I don't think they would offer any incentives to get Southwest.

Looking at Denver, would they go DEN-ABQ - not too wise, as Frontier and United have this. DEN-SLC, nope Delta and United. Continental pulled out of Denver, think there are many other cities that could be more profitable.

I'd love to see Southwest in Denver but don't see it for some time. Colorado Springs maybe, but airlines that go in there have a history of leaving or bankruptcy - thinking of Western Pacific.