Long believed his brother dying was the beginning of the end. That's when he relapsed in Velvet Revolver and it was just a slow circling of the drain, at that point. In the last stage, he'd surrounded himself with "yes" people, or people who, at best, weren't going to stand up to what he was doing and, at worst, were part of the problem.
It's almost as if the will to "try" anymore was just slowly sucked out of him and he coasted until the inevitable end. It seems as if he pushed his kids away, his long time friends, he racked up debt/stopped paying his bills, and almost didn't even seem to care he was playing tiny venues that weren't selling out.
And here's the thing--society fails people like him. Yes, we all make individual decisions of which there are consequences. But drugs and alcohol in and of themselves aren't a criminal matter. Addiction is a medical issue. People with really bad habits, which is a larger group, are people who need some sort of help, not a criminal record. The arrests, the making fun of him for being a junkie, all things that, in the future, we will look back on as contributing to the problem and not solving it.