They're a 1 - 6 team playing like a 1 - 6 team. They're just not that good. Whether it's the duds where they don't even show up to the game (i.e. Seattle (offense), Dallas) or the close last minute games that they failed to close out (Philly, TB), or the complete and epic unwinding games (Chargers), they flat out just stink.
Everyone on this starting offensive line would be a backup on most other teams, or out on the street, with the exception of Pugh who, at best, is a B level OL, and Richburg who is C+. That's the Achilles heel on this team. The game is won and lost in the trenches. Or more accurately, if you don't have at least an average to above average line, your offense really doesn't stand a chance.
The defense, despite the inconsistency and far from being great, would be in much better shape if they weren't so gassed and relied upon due to the offense not being able to hold onto the ball.