^^^ Not that I disagree with you at all but I bet someone said the exact same things about Wes Welker.
Wes Welkers don't come around that often. Just like Tom Brady's doesn't mean that you should wait until the 6th round to draft a QB.
Also there is a difference between WW and Marvin Austin, WW wasn't drafted, MA was a 2nd round pick.
Typically UDFAs have a very very small window to prove they warrant making the team. The Chargers gave WW the 1 training camp and cut him after week 1. And they offered him a spot on the practice squad so it wasn't like they didn't see anything in him.
MA was given one full year and one year on IR by the Giants. And all the chances typically afforded someone the team invested a 2nd round pick in. And didn't want him for the PS.