I think its just becouse most of the cool old mods and members have no time for stuff like gaming and chatting online. I don't even game as much as I used to or even 10% as much. This site is really nice and I check it daily, but I am very disappointed at the inactivity.
A good point, it's not the site itself that lacks flare, it's the members inside since there are so few active ones now. It's kind of like a generation has moved on (like myself, I'm still trying to check in every several days though). I guess my advice would be to try the same method that started this place. Hone in on one interest, most likely a game (originally it was RuneScape), and start something there for CurvedSpace. People come to these community sites because they share the same interest with everyone and can meet people, and help themselves progress through that interest.