The landing fee issue is legitimate, and PDX is not the only example of that. It could very well mean the difference between flights being break even or loss leading. Too many airports don't get that when they go build new crystal palaces with jet bridges.
If yields at PDX are so high, why is it mostly QX metal? If the guys in RM thought there was demand for another flight, it would be there. And again, RM sets the overbooking levels, not the station.
IIRC, the only reason PDX-ORD stayed around was the tag from/to EUG, as the airplane was catered and overnighted in EUG with practically no cost. When that went away in 1993, the nonstops to ORD got more expensive..
Shocking it may be, the GM going to TUS probably knows more about station outsourcings than a lot of GM's -- I was project managing the process of closing his station (he was an agent back then) and a dozen others around 1993; two years later, he took over the project managing piece when I moved on to another group.
So, yes, he knows more tricks about how to keep a station open than a lot of GM's do. It doesn't mean he can affect the number of flights or how they're priced & sold, though.