The NFL hasn't really completely confirmed how they choose refs for big games, but this article helps a bit:
Especially the end about Bolger, and how he hadn't even ref'd a conference game yet.
Also no one can do back to back Superbowls, so the BEST refs aren't getting in there. You really have small competition to get into a Super Bowl game/play off game because they have more refs in those than a normal game I believe.
But in the end they truly, really don't have anything to be worried about. When was a ref fired for bad performance? I don't remember, if they have, please tell me. They pretty much of a cozy part time job they never have to worry about.
You're arguing about poo that is more than likely nothing but what the Officials Union added to their contracts so more of their constituents could be part of the Super Bowl as long as they were in the Top 5. You just said earlier that your quality of officiating has NO bearing on who gets playoff games, however it is clearly stated that they pick from the best. However one team is below average, they are not random.