It's frustrating from OTH also. I've seen fares to PHX and FAT half as much than directly to SFO. I would like to take my wife to SFO for a long weekend, but $400+ is a little steep.
I wonder if UAX is trying to limit local traffic this way. I don't understand this as QX use to be quite full most of the time when they were here running 4 flights a day to PDX on their Dash-80's. I suppose they can carry more golf clubs on the EMB-120 by restricting passengers. I've grown to like the EMB-120, but it certainly is limiting.