Lets examine that. 6 years is an eternity in games. People move on to other games. Or simply dont play as much if at all. Regardless of the mod, not just this one. Mods themselves either evolve over time or they stagnate and become repetitive. Believe it or not people to get bored of freezetag. Also, clans have lifetimes big and small. There comes a time where more people leave or become inactive, due to different reasons, than new ones that join. Those that do is because they see something they like. I suppose admins can also ask themselves whether or not their criteria for an 'invite' is less than it once was to keep the numbers up.
As for the jacket, yes its very good against tubes specifically. But that is because its really easy to get kills with tubes. For those that are experienced with them. So this is the balance.