It seems to be: “Here’s a guy whose life is shit. Watch it get worse and worse until the only thing for him to do is die. The End.” The film’s protagonist is summed up by his daughter: “You’re a fuck-up, a walking fuck-up”. And that’s – pretty much – all there is to it.
You feel that Aronovsky starts off by saying “let’s take a genre, and play with it.” But he doesn’t play with it, he just strips it of any hope, of any of those things that seem, for some, to smack of suspect “Hollywood” elements.
You also get the feeling that if you said this to Aronovsky he would tell you that you weren’t able for the true bleakness of many people’s lives; that a lot of the times, fuck-ups don’t come good; that the little man doesn’t get the title shot, and if he ever did, he would probably get killed in the ring.