PHX does not have the population base to support European flights because it takes two aircraft to operate one route. That doubles the expenses in a market that has COMPARATIVELY little business traffic to Europe.
This statement would only be true, if those aircraft were utilized solely on the European routes, and sitting idle on the ground the rest of the time. That that would indeed be foolish. On the other hand, I think US is missing out on a unique opportunity, if they didn't try to capture the long-haul potential here. There seems to be a general tendency to downplay the strength of Phoenix as a hub. Bu after all, thanks to Phoenix, America West was able to grow big and powerful enough to take over the old US Airways ...
Obviously, as it stands right now, US doesn't have enough lift to set up a long-haul operation here. But that will change in the years to come, if all the A330s are delivered as scheduled. If so, there should be enough potential for a few routes to Europe, including LHR, FRA and CDG. After all, British Airways flies a B747 here, not just the smaller 777.
In order to optimize aircraft utilization, aircraft should ideally fly alternately on eastern and either western or southern routes, i.e to Hawaii or South America. IMHO, it would also make more sense for US to fly to China from PHX rather than from PHL. It would btw save US the additional expenses on a small subfleet for Asian flights.
And while I am at it, a few remarks on GIG: how many flights from the East Coast to Brazil is US going to compete with the coming fall? On the flipside, US could offer the most convenient connection to Brazil for the entire western seaboard via PHX. There are no nonstops to South America from anywhere on the West Coast. US could bank on its own as well as United's western frequent flyer base.
It certainly requires some thinking out of the box, and that's unfortunately something that's often missing in our corporate culture.