WN's own statement was quite clear: they can make more money with less hassle by flying those aircraft on other routes. SFO is also a hub airport, beyond receiving tourists into the city, it feeds many more connecting travellers through to/from Pacifc destinations. WN is a purely point-to-point mover of travellers. It figures service to the Bay area can be just as well provided into Oakland and San José without putting up with all these SFO problems. It's economics nd nothing more.