Ok, here goes. I'm in San Diego, born and raised here, and with the exceptions of college and a couple relatively short-term jobs, I've lived here my entire 44 years. I'm a casual sports fan, but if pressed I'd claim the Chargers as "my" team even though I never really paid too much attention to them. I'd check the results and get frustrated with them, and them move on with my life. I could probably count the number of Chargers games I've attended on two hands.
That said, I'm relatively smart and observant, local, and here's what I see: LA is not the Spanos family's long-term goal; rather, Orange County is.
During the runup to last year's NFL owner's vote on relocation, the Chargers' argument for moving included the claim that a relatively large percentage of their fans and non-TV revenue came from Orange County. The Chargers said they couldn't allow another team to move into LA because that team might eat into the Chargers' OC revenues. Therefore, if any team were to move there, it should be the Chargers. Obviously, things didn't go well for the Spanos' argument, and they ended up teaming up with the Raiders in their failed Carson joint venture. Things went really badly when the owners did what Spanos interpreted as a back stabbing move when the Rams (read: ultra rich Stan Kroenke) were greenlighted for LA and the Chargers and Raiders were shunted aside.
Look at who the partners in the Carson plan were, and you'll see that Bob Iger, the CEO of the Walt Disney Company, was a major participant. Iger has the chops, both personally and professionally, to get things done in Orange County, and an NFL presence in or around Anaheim would dovetail nicely with Disney's presence there. There's already a stadium there that was sort of renovated for the MLB's Angels some years ago, so there's real estate available (it's also virtually next door to the Honda Center, which is where the NHL's Ducks play, and the surrounding land is already being redeveloped into mixed use). That stadium used to house both the Angels and the Rams before the St. Louis Rams days. Plus, the Anaheim stadium has the main north-south Amtrak and Metrolink line running alongside its parking lot, and the local station is in the parking lot. There's a huge new station being built immediately to the south, which will replace the mere platform that's there now. I think Iger's plan is to turn that entire area into a residential/sports/entertainment mega complex, and an NFL team is exactly what he wants there.
I think Spanos' experience with being backstabbed by the NFL made him extremely wary of the purported promises he was receiving that he would be allowed to move there before the Raiders (despite the Vegas Raiders talk we've been hearing). I think he felt very insecure in his ability to protect that OC revenue, and his deadline to opt into LA at the Rams' stadium was almost up. He received an extension, but I can't imagine that he wasn't afraid of the other owners' machinations to prevent him from moving. He'd already been backstabbed once, and he wasn't about to let it happen again.
Therefore, I think the decision to actually move was a relatively hasty and impulsive one. For evidence of this, see the horrible non-logo logo they revealed yesterday. The first thing they needed to present and advance was their new brand, and they trotted out some POS logo that looks like clipart. Dean Spanos then began his new job of promotion, which he absolutely isn't built for - he, an heir who has done nothing in life but enjoy his father's wealth*, was virtually silent throughout the entire last two years in San Diego: first throughout the first effort to move, and then even during the crucial initiative effort to approve a new tax/stadium plan here. He's simply not a speaker. He was forced into that role quickly yesterday, and I think that's why he put his foot in his mouth as to OC. That's also why the decision was announced by a letter on the Chargers' website, and not via a public statement by Spanos. (*Note also that the Spanos family is something like the second "poorest" NFL ownership family. I think Dean knew he was in over his head when dealing with the likes of Jerry Jones, Robert Kraft, etc.)
Add to that Dean Spanos' letter announcing the move, noting that he included a time limit on the Chargers' stay in LA - 25-30 years. He's hedging on where the team will be long-term.
I could keep going, but I've exhausted my Slowtwitch time for today.
War is god