The problem is that there are also reasons to think that he wasn't offed. First and foremost, there was no reason for it. Sure, he was a gangster and it could have happened at any time, I suppose, but they just resolved the gang war in a way that wouldn't have indicated any greater threat to Tony. Like I said before, if he was killed, it might just as well have been a random act. Hell, it could have been a one-off character from season 1 that did it, but if you don't provide any insight to that, what's the point? Also, why bother flipping Carlo if your intention is for him to be dead anyway? If, as you imply, there was a reason for every single element, then what was the point of that?
You guys have made some fine points, and I now conceded that it's entirely possible that's what Chase intended, but it was obviously done in a way that was ambiguous. It still seems just as plausible to me that he was just depressed and life went on for them all.
And by the way, if he got popped by MOG coming from the head, he shot him with the gun more than 12" away. You'd think that a mafia hitman approaching from behind with the element of surprise would have put the gun right up to him.