Again, most teams that have made it to a Super Bowl have had a top-notch QB. Landry had Staubach. Johnson had Aikman. Belichick had Brady. If we're going to ding one for that, we have to ding the rest.
However, I do absolutely agree that it shows (outside of a few examples) that you need to go into a good QB situation. That's why I would only consider the Chargers if I was Quinn. In Washington, he'd get to pick his QB with the No. 2 pick, but that also means you sink or swim with the rookie. By the time, he's ready to swim, you may be gone.