Minecraft has been released over the past two years, just hides in Beta to give people expectations.. because Notch is a [censored]. Aside from that it's a big fat time sync, people will stop playing it as soon as a game keeps them occupied this year.. Skyrim, for example.
I certainly wouldn't pay £18-19 pounds for when it decides to bunk up in price to tell everyone "YEAH MY GAME IS FINISHED NOW" then realise it's still the same boring game you've played for the last year or so. Because I'll be playing Skyrim.