it's also not just watching film of their own games, but film of what other teams are doing - how they're guarding, switching, fighting thru screens etc etc etc - and watching it with someone to point out what needs to be pointed out, not just with each other but with a coach who should have more interest in the team as a whole than any one particular player - it really has to come from a coach and not a fellow team mate (not necessarily the head coach but someone on the coaching staff)
and so much depends on the quality of the film that is put together too, some of you make it sound like it's just a matter of watching a replay of the last game