My favorite part about this game of musical chairs is the possibility that Stan Kroenke gets voted down and then has to continue running his franchise in St Louis after having just shat all over it very publicly and vehemently. Maybe if that happens, the fans will force a Donald Sterling-esque situation on him.
Say what you will about Mark Davis's competence, haircut and eccentricities, he does seem to genuinely care about his team's success and, up to a point, his fans. If he can get what he needs for his franchise to remain stable amidst the lion's den of NFL ownership, more power to him.
For what it's worth LA is likely to have 2.75 million tickets to sell next fall for NFL, USC and UCLA football. That is a hell of a lot of tickets in a largely ambivalent NFL town for four teams that didn't qualify for a playoff or major bowl game this year.
There are a few midsize, passionate markets that sell more tickets relative to their population. Pittsburgh for example will sell about a million tickets for Steelers and Pitt football in a market about one fifth the size of LA. But I suspect there will be an awful lot of empty seats at NFL games at the Coliseum next year.
We do have a precedent: the NY Baseball Giants & Brooklyn Dodgers. Here's attendance pre and post 1957:
Both teams immediately and sustainably doubled their attendance, roughly. I'm not sure where the Raiders, Chargers and Rams rank on season-ticket waiting lists, but I strongly suspect attendance would not be an issue. There are enough people in southern california that a solid majority of them can give zero shits about the NFL in general, much less the new town teams, and have those teams still be fine.
edit: obviously, no analogy is perfect, but in those days MLB was not a national brand and there were few if any pre-existing Dodgers and Giants fans in california. The right product hit the right market at the right time. Obviously the Raiders would have the easiest path of the 3 franchises, but I don't think any of them would end up dead in the water, certainly not for any appreciable length of time.