Closest parallel I can think of was the 1988 MNF disaster:
Several similarities. Denver had a 24-point lead, at home, on Monday night, vs. division rival. The Raiders clicked on offense in the 2d half while their D intercepted Elway three times (and once more in OT to set up the game winning FG)
Hurt like hell. In some ways it was worse, because it dropped Denver to 1-3.
But what happened then?
Denver rebounded to win the next three in a row and finished the season 2d in the AFC West at 8-8 - a game ahead of the Raider team that swept them that year.
Reeves wasn't fired. Elway wasn't benched. No one hit the panic button and in 1989 Denver won the division again. In fact, they won the AFC title that season.
So, like several people mentioned above, this really shouldn't be a franchise-crushing event. I think the anger among SD fans has more to do with the feeling that the team has consistently underachieved for several seasons now relative to the fans' expectations.