Yeah there is quite a solid chance that something like a `gmod2` could happen. It is just that they are probably not gonna add that big of a update, its just gonna be a way to earn cash from players having to buy a extra update. I have lost my gmod account (steam acc with it) and so i do not play anymore, however i still believe that would be scamming. If they get a big enough update to call it gmod2 then its fine, but i do not know what is the big thing they could add which would make people buy another game, and lose their previous data.