PHX is certainly a big US without any transoceanic international flights (save BA) - but that is because of the poor quality of its population base. The city has relied on retirees and snowbirds far too much for economic expansion; as opposed to building a vibrant economy that can fill seats up front. In short, Phoenix, at least in its 55+ only parts, is a large death camp in the desert for mostly midwestern retirees hunkered down in cheap tract homes awaiting their ends.
I would disagree with your statement according to census data :
The median age in Phoenix was 32.2, making it among the youngest cities in the area. Tolleson was the youngest, at 26.6. Sun City is 73.6 but its a small number compared to the Phoenix population. There is also many Corporations based in Phoenix. Intel has a large presence, Google, First Solar, Go Daddy, Knight Trucking, Swift Trucking, Pet Smart, Ping etc etc.
The rumors in Phoenix for years have talked about a DBX flight. It is also said that the COP is actively courting overseas flights (thier dream is TYO). Phoenix and Dubai have a lot in common, Heat, Sun, and Sand!