Part of the inactivity is just people growing up. Pretty much all of the mods started here in High School and are now in further education or the workforce. We can't be active anymore, so we need fresh faces to become active.
We'll get a burst of activity at the next game release, so there's always that. I've seen larger periods of inactivity before.
I've been here since 2011 and have seen two CSS changes. I've seen users come and go. Fritjof, Will, DT, JCM, Spoink, Flame, Sempi, the list will continue to grow. Eventually I'll be gone too and most people won't even know who I was.
The end is inevitable. You just have to make do with what you have. It's kinda like life, you know.
