It's a new coaching staff and they don't know what they don't know...
It took Dick Jauron watching NT Kriss Jenkins manhandle three Bills players by himself and still sack the QB before they drafted Eric Wood in the first round and Andy Levitre in the second. Meanwhile, they didn't replace a top OT in Jason Peters until Buddy Nix drafted Cordy Glenn with a second round pick.
These new coaching staffs learn as they go as McD knows defense so that is where he wants to put most of his marbles. What these men don't comprehend is that it takes five top linemen to make a solid, cohesive offensive line good enough to allow the team to win playoff games. Not to mention quality backup linemen in case of injuries. This current roster has neither!