Tons of MMOs have been allowing early/beta access to players who wish to go ahead and buy/play their game. Players get to experience the game early, assist with support, all while getting the social interaction that defines MMOs. In short, it works for MMOs.
But lately more and more single player games have been selling early access to unfinished games.
I don't understand... You're paying for a unfinished game with none of the benefits of the MMO genre the trend was stolen from.
Early Access? for a single player game? No thank you!