The fact that we got schooled by the calcified remains of David Lee says it all, I think.
overly simplistic. overly pessimistic. the latter i expect from you. the former i dont.
I didn't watch the game, so I can't say more. But from what I've seen so far this season, rebounding is an issue. I had concerns about Horford's declining rebounding numbers, and while there was the odd chance that it was system-related in ATL, it seems to be more of the same with us, so while in many aspects he's an upgrade over Sullinger, that upgrade is not big enough to offset the fact that he can't clean up the glass. So right now we have 5 bigs in our rotation that can't rebound. And Jordan Mickey. Forgive me if I choose to be a bit pessimistic about that 
good points and thanks for making them. some of the rebounds lost tonight are exactly as you write above. some were simply bad luck. but the underlying problem you mention is there nonetheless.
the celtics dont have to solve each and every woe in one season for two. better to be patient and get someone you really want instead of a so-so/slightly better player who would eat up salary cap and limit the team later.
if ainge doesnt get a good big man this year, i trust he will in the off season or draft.
oh, and a tp for the nice post above. thanks.