I can’t recall any game suddenly becoming so much popular so long after it’s release that numbers suddenly rise to the extent some people are hoping for. Aye, WoW and other like minded games have peaks and troughs, but that’s usually because there’s a number of people who return for the new content and then leave again. Same goes for any game. The problem is, new player numbers rarely make much of a difference. Either get it right at the beginning or close to the beginning and you stand a chance.
This game is never going to become super popular now. That ship has sailed. Maybe making it a F2P would boost numbers, but even mediocre F2P games suffer in the end if the important parts of the game suck. I know i wouldn’t waste the HDD space required for this even if it was free.