extremely poor but why?

The trade mark of most top 10, conference winning, teams is a dominate (or at least above average)  offensive line. Coming into the season everyone looked at the depth chart and saw SR, SR, JR, SR, GR. That combined with the addition of,  what was perceived to be, one of the best O line coaches in the south and we were destined to run right over most of the ACC. Instead, Clemson has won despite the offensive line not because of the offensive line. We've played some talented groups including Fla St, UNC, and GT and we didnt get a push against thier fronts but, the most disturbing games have come against Troy, Wofford, and Wake. Against the later mentioned teams we couldn't open holes even though Clemson's offensive line were giants when compared to their defensive line counterpart. I have some theories on why this is the case but, no real answer. My guess is:

• the players were soft coming out of high school (Ard or Strelow has eluded to this)
•  not enough live practice against our def line
• not enough emphasis on run blocking
• not enough Olympic weightlifting in their training

I dont know the answer but i enjoy discussing it none the less. I do feel its a combination of all of these factors.