FWIW Matt Flynn would have probably been a starter nearly anywhere else at that time (Dude set records as a backup that are still in there) but we had Rodgers, so he was out backup. In fact he almost WAS out starter, but McMuffin did not like how he practiced even though his in game intensity was really good. And we almost won that game against the Tom Brady led patriots, too. Same guy came back from three scores to beat peak Romo Cowboys (the very game that originated the Never go full Romo meme). Dude just had the worst luck for where he ended up and was always destined to be the second guy.
But most of that list is absolutely some positively mediocre QB talent, at best. That having been said, Purdy had one of the better debuts of any backup QB I can remember since maybe Hostetler. I think the real takeaway here is that the incredible SF D and running attack have obfuscated how much sub par QB play that they have been able to get away with in recent years. In the current era where every prospect is a non-pocket RPO guy (who is likely to get hurt), I think his stock really went up with that game.