Moving to LA is an impossible task for this particular team. This is all about the mechanics of deception leverage.
No need to market a team that's been in town for 52 years.
There is no fan base in LA for the Chargers. Mr. Spanos knows that LA folks won't continue to drive down to San Diego to watch the Cowboys, the Raiders, the Steelers, the Packers, when they can easily do so right there in LA. And probably do it twice per season if two teams relocate there.
That would mean that Mr. Spanos would have to convince his season ticket holders to renew while knowing they won't be able to scalp them to visiting fans anymore. Buy a Charger ticket to watch the Chargers, not to make your money back by selling to the Steelers. It isn't clear if every Chargers season ticket holder would continue under that condition.