Well, I do think you'd have to account for a few other things.
The fact that 2 OL were drafted in the past NFL draft and a third who was a starter and was on track to a bright future (Jaivorio) is probably out of football.
The fact that we were pulling in a ridiculous class at OL before BC was fired: Bryce Givens, Dan Hoch, Trevor Robinson...some of these guys are starting at other Div-1 programs.
The fact that this is Bo's second year. Two classes of BC's guys have graduated. And I think having two of his guys on the 2-deep seems much more ... normal? than an indictment. And to the extent that it is an indictment of something, it may be more on the last minute OL he pulled in his first year after everyone else jumped ship than anything else. I am optimistic about those kids' futures though (Sirles, Qvale)
i don't want to trash our guys, but i would say the following players left by the previous staff are what i would consider "quality":
murtha
slauson
mike smith
hickman
williams
jaivario
the following still have potential to be quality:
caputo (walk-on)
marcel
the rest are just guys:
dj jones
mike huff
andy christensen
barrett
so, they left us with 6 quality linemen. it's our bad luck that of those 6, two were seniors and the rest have struggled with injuries this year (with jaivario being obviously the biggest blow).
the 2007 recruiting class netted us exactly TWO linemen total: jaivario (stud) and marcel, a project that still needs more time in the weight room.
the 2006 class had the following:
nicks
cruz barrett
victory haines
ricky henry (didn't qualify, resigned in 2008)
hickman
williams
dj jones
mike smith (recruited as a defensive end)
giving us a juco that was pretty good for one season (nicks) and THREE quality high school linemen in smith, hickman and williams - a good class.
the 2005 class had the following:
pasteur
picou
picou
roark
giving us exactly ZERO quality linemen.
not exactly an impressive record of success in leaving us a "stacked" offensive line. yes, they appeared to have some good ones lined up for the 2008 class, but who's to say they would have stuck anyways, given the sinking ship that was cally's last season.
(and for what it's worth, givens doesn't appear to be very good, robinson appeared to be getting a lot of pressure to go to ND, and hoch probably was going to follow gabbert, who decommitted before the firing.)