Some of them, others remain a little more.
However, we can't blame them for being "corpses" as dc20081222 describes, sometimes it takes too much time to get a league, and people wants to play ASAP.
But we must remember, Admin already said that they'd assign new people to a league everyday if they could, but game database gives serious issues if they make it in matchdays.
I believe GKO staff must be searching for a solution (maybe already have one, i don't know) and people gave some interesting solutions (game tutorial, friendly league while you're in waiting list), i'm afraid we must wait to see what comes next.
I know it's disturbing (i'm a player in a league with unactive users too) but i'm afraid all we can do is wait, Admin (and all GKO staff) are not stupid, they're really aware of this issue, a fix must be on the way for sure.