If you read the anecdotes and the counter-examples in this thread, it seems to matter. The idea seems to be that a game is not dead for as long as someone is playing it. Many criteria in the OP revolve around the personal experience which may, as we all know, vary a lot. My point was: those are not good criteria, because we don't know and we cannot know.
You have a good point, though. If you look RPGs as an industry, a game could be considered dead, if it was not a viable business, e.g., it would not provide full time employment for more than one or two or however many people. Outside of the few exceptions, RPGs are a cottage industry to begin with, so through the requirement of full time employment much of the scene would appear dead. Maybe it is, we just don't know it yet. Some of the ideas brewing in it will probably survive. It's like architectural styles.