Well i can just talk for myself:

I have written it somewhere else, the players that are active you mentioned play nearly only on the RPG,
i although i tried sometimes, i really dont like that style, so when im on sometimes, i see you but i dont join
and go play on another server.

Furthermore on our other Server mostly play not good Players (mentioned it somewhere else aswell),
so its not motivating for me to play against them alone, and on our Beginner and FS Server im not a big fan of the tracks.

Last, the activity on our Events was becoming really low and it was not possible to plan them,
because nearly anyone made a clear post like "i will come on that date and that time",
so i didnt want to "waste" my time alone at home hoping for some to come to play an hour with,
because that would mean i wouldnt visit friends or girlfriend on that day (and because if have to go by train,
that would mean i dont see them the whole evening although the event is only an hour or so).

I dont have so much time atm. And i dont want to play tm, if i want to play something. but this will change sometimes, i think. When i am on, nearly n0obody is on, or on RPG or...

I think I would play on the shortie server or fs or beginner too
No problem with that.
But all from R4a in my buddielist playing on the rpg server, so I play with them, and not on the shortie

I've kinda gotten obsessed with united servers again...

its a very good question