Bubbles doesn't kill a kid, he doesn't ever get clean. He needed to bottom out. It's a very libertarian view of the social contract, actually. Bubbles can never bottom out while he has the support of the state. It gives him just enough to sustain him. As soon as the state evaporates (Herc bails on him), Bubbles has no choice but to fend for himself, to initially disastrous consequences. Bubbles survives this temporary period, learns to be self sufficient and thrives. Randian stuff from David Simon, here.
Very good point here.