Well I mean, of course you think it's a rip off, but you have to understand, that running the servers, putting up new servers, maintenance, updates, and hiring staff people all cost money, and just selling the game isn't going to cut it, because in order to keep everything up, you'd have to constantly bring in thousands of new players, and only SO many people can get the games.
And anyways, what's the average rate for a game anyways? $9? I'll round it up to at least $10.
That means all you have to do, is once a month, mow ONE person's yard. That's really not that much, if you guys would get your asses off the computer every once in a while.
But, I don't think I'd ever pay a monthly fee for a game, cept maybe Graal.