A Blindside?

Is there something we're missing in all this? Remember a few yrs back when GMs decided RBs weren't very valuable? That's when GMs decided/realized that most RBs were a function of their system and their O line. Denver produced 4 or 5 different Pro Bowlers in 6-7 yrs. Didn't matter if it was Terrell Davis, Mike Anderson or Clinton Portis running the rock. 

Has there been some such evaluation at the QB position that I'm unaware of? Have GMs in Phoenix and Minneapolis decided they're so smart they can plug someone into their system and win, so it's not wise to spend on a guy like McNabb? Or is Donovan secretly rated very poorly by all the GMs of the world because he's not accurate? Because it's all very confusing. I really don't understand the lack of interest in McNabb. 

The Clayton pts are all well noted, but there are a half dozen teams that are 6-8 win teams that would instantly transformed into AFC or NFC title contenders with him. I feel as if we're in a Michael Lewis/Blind Side/Steve Wallace moment, where the entire shape of the game is being changed and we can't all see above the day-to-day fray to realize how significant a moment this is.