Moving the team to San Antonio would also bring in the Austin area...it would be a central Texas team. People from Austin are also die-hard Spurs fans as well. LA would be taking a major L if they can't bring the Raiders back.
That doesn't compare to having Los Angeles all to yourself. Hell, the Raiders would have the whole state of California cuz it would be people from NorCal coming south instead of SoCal fans going north. Mark Davis has lived to see the Raiders in LA before so he knows the following there and the amount of money to be had in a market already tailor made for his team because of a history of success.
I just can't see Oakland putting up the level of funding needed to keep the team. I just hope we finally become a winning team again so LA's perks can be exploited even more. Hell, keep the preseason games in Oakland.