Just because they fly to SFO doesn't mean they won't fly to OAK. Lots of people prefer OAK, particularly WN people. When are they going to add a non-stop to SJC from PHL and CLT?
The bottom line is that if the Wise Ones think that a flt to OAK from CLT will somehow give them an advantage over WN, they will add it. It seems to me that everything revolves around competing with WN. If you focus too much on one "enemy" you sometimes lose sight of the big picture and if the guys in Tempuraville don't pay attention to AA and UA, US will be lose even if they win against WN. Biz pax in the East are different than Biz pax in the west.