The Cowboys had some good squads pre-2011 and then went into transition. I thought they were fairly average last year, this year they are playing bad (although against Bears pass blocking was okay) but a lot of other teams are as well.
I do agree about the excuses, it is what it is... I think talking about trying to upgrade with new players is more of an off-season discussion.
It is hard, but some teams have compensated for their deficiencies at o-line with play elsewhere to find a lot of success in the past. Steelers with Big Ben buying time, Giants with Eli hitting the hot route to Cruz all day last year, Cardinals with Kurt Warner making quick throws to Boldin and jump balls to Fitz, Bears utilizing a great screen game with some down-field shots, etc etc...