Of course the players need to be held accountable. They need to be held accountable by the coach. He is the one that is there to teach them, and to motivate them. If they are not doing what he is teaching, not into the games, etc. he either needs to use some disciplinary measures to get their attention (like the haircut thing), teach them better, or simplify what he is teaching them.
If only one or two guys was having a problem, I would be looking at those guys as needing to be fixed. Since it is most of team that is failing, it is something more systemic, and that is what the coach needs to be held accountable for.