The questions is not wether we become a GM or not.
The question is, who is interested in work that is not paid? Well, I mean, being the/a GM of a online game is a nice "job" even when it is not paid, but who wants to do this for a almost dead game and that much of restriction to make things happen?
Personally I find as a member you can often do way more for a game, due to the restrictions. But having a "GM" do it, often looks better for the game so both got pro's and cons. It kind of depends what you're trying to achieve.
If you're someone who doesn't mind throwing gifts around, its incredibly easy to make up some events and run them. You're also allowed to speak your mind rather than the usual copy paste because you're bound by rules. As GM you're not allowed to help with general gameplay also, so helping people through a dungeon is a big no, etc.