My Guess is thus - people maybe play on a few servers and they either get bored or banned - everybody it seems wants to be GM so they can get to level 50+, have the best gear on and spawn mobs but they forget something very important when they create these servers.........
It requires a machine to be running 24/7 at 100% cpu useage, maybe even 2 machines if you have SQL on another box like I used to. On top of this constant HUM from the machines, the connection you think is so uber suddenly becomes next to useless as anything you do will inpact the server so no voice chatting, video chats or uploading files to your mates via MSN as this will lag the server to the point of stopping it dead.
They also forget that they need to spend a LOT of time adding stuff, going through the bugs and helping players and they struggle with the wrong files and cannot see the NPC or new mobs etc. If they set the exp too high or the Items on Uber stats, then they spend all there time on the forum as people moan daft about how this is too easy, the drops are all wrong (cos everybody is a mir3 expert) and the exp for that mob is not right.... etc....
Eventually they sit back and say - hell wait a minute - this is costing me money and time yet nobody is paying me - so they add a Donation Page / link and no body sends any dosh - so as with so many - its falls off the scope and the server dies - another one down the pan.
My advice is simple - sure run a server, maybe just you and your mates to mess about with, least then you can switch it off and use your connection - a live server feels great - 50+ people online - whoooo - but at the end of the day - all you gain is the knowlege that people play on your rig....