Ollie certainly deserves a majority of the blame, but I also believe that this roster is seriously flawed. The two biggest flaws, IMO, are not having an experienced PG; and having core players who in reality, are mostly one-trick-ponies. I'm referring to Brimah, Hamilton, Gibbs and Purvis -- players who have failed to develop fully, have yet to become complete players, and who play like role players, not stars.
They improve their area of strength, but mostly fail to expand beyond that.
I put Brimah at the top of that list simply because after almost 3 years, he's still not much more than just a tall kid who can block shots. He simply hasn't grown in ways that can't be measured with only a ruler. But the same is nearly true of Hamilton. He's not one-trick, but mostly, he's just the same player he was when he came into the program.
Gibbs frustrates me. I find him hard to watch, but I also have some sympathy for him because he's been put in a role, as PG, that he's not qualified to play.
As for Purvis, I consider him a balanced player -- half of what he does helps his own team; half helps the opponent.
So is all of this really Ollie's fault? Maybe.