25% of the Chargers' season ticket holders live in Orange or LA counties. That's why Spanos is so afraid of the potential for another team to move to LA, and has been threatening to block it. He's allegedly wrangled up enough votes to block Kroenke's move (although it remains to be seen if Kroenke cares; it would be pretty cool if he just said **** that and moved anyway). The reason why he's gone through all this effort is because he knows that the LA market needs to be unoccupied for San Diego to remain a viable home for the Chargers. Why? Because, going back to the first sentence of this paragraph, the team relies on the LA/OC markets even to get to the meager level of support that it has managed.
And this is consistent with what I've seen. I live in LA county, so I think I can state on pretty good authority that there are lots of Chargers fans here. More people care about the Raiders, but the LA market is so huge that, if even a fraction of people in the area become Chargers fans, they'll be in a much better position than they are now. It's San Diego that pretty clearly doesn't care about the Chargers. When I went to the Sunday night game a couple months ago, we outnumbered Chargers fans by least 2 to 1, probably more.
I think a lot of people are underselling the LA market here. The Rams had strong attendance right up until people got wind of a relocation because the widow who inherited the team was from St. Louis and wanted to take it home with her. USC and UCLA both get a ton of support. I am 100% certain that, even with two teams in LA, neither would have the attendance/local support problems that the Chargers are having down in San Diego. LA fans have become fine with not having an NFL team, because what else are you going to do when the league bails on you for 20 years, only to use your city as a threat to extort more money out of every other league city? That doesn't mean that they don't want a team to support. People here want a team, they're just not willing to put up public money to get it done. And why should they? They know they don't have to. LA is playing the long game, and it's clearly working. They're going to get a team, and they're not going to have to give some billionaire massive taxpayer-funded handouts to make it happen.
As much as San Diego fans have a massive inferiority complex that leads to them hating LA )for reasons that have never been totally clear to me, nobody here minds San Diego), a lot of them will stay Chargers fans. The 25% of their season ticket holders who are in LA/OC will actually have the team closer to them if it's in Carson. Carson is a really interesting location, because it's south of the actual city of LA. It's right next to Long Beach (where I live), and Long Beach is on the OC county line. It's as close to Anaheim as it is to the city of LA. Anaheim will be a huge source of support for the Chargers if they move.