I disagree about SWA and LAS.LAS was a money maker for years, but not any more. There are just not that many passengers going into LAS now and it doesn't make sense to keep all that flying. It was great to have 300+ flights there, but even then the margin was razor thin.
I have no doubt you'll see SWA rethinking LAS soon.
And I wouldn't be too worried about PHX.
I cant speak on a daily basis, But the wife and I just tried to non rev out of LAS last weekend. We could have used US, SWA, or Air Tran. We waited through twelve hours of southwest blender like a pinball going from gate gate through 8 flights before we finally called it a night and got the last seats out to an intermedite stop on SWA the next day (our third try for that day). I can truly say that there was not a single seat that left without a butt in it that weekend day going anywhere, and at least not East on Airtran or US. Dont know if it is like that all the time, but it sure was amazing last weekend!
The SWA gates were a mad house, so we walked over to the US gates where it was peaceful and serene. That would worry me...