The technical side of the server is just half the battle. And if you're really serious about running a server that you expect dozens of players to play, I dare say it's the easier half.
We've had several extremely popular servers with very technically knowledgeable people running them, up and disappear from the very same issues that plague pay-for MMO services (balance, content, "people" issues, and so on).
One of the famous PvP servers run by a pair of ex emu devs was abruptly shut down after too many players felt that a couple of the GM's were corrupt and untrustworthy.
Another server that has enjoyed a large following for the past several months is about to make a very controversial decision with what direction it wants to go in the future, and if this decision is not made with the utmost care and consideration, it could spell the unfortunate end of that one as well.
There are quite a few servers out there that are content to just run with 10-15 people at prime time (and sometimes not even that). For those that are ambitious enough to try for a server with a population beyond that, I have to admire not only the work they put in to get it set up, but the issues they have to deal with on a day to day basis.
And it gives you a window into what the game companies have to deal with constantly too. The very same people play here, just in smaller proportions
