You can do it now if you want. You only have to download a private server, and run in on your own hardware. It’s not taxing at all if you’re the only one playing.
For an MMO, it’s perfectly reasonable to call it dead if the population drops below the point where someone can reasonably participate in all available activities.
The fact that people are able to dink around alone on their own private servers doesn’t really mean the game is alive.