As soon as possible for each individual, it isn't possible right now for EVERYONE to be in the game. Their options were to hose the servers so no one could play, or bring in a few at a time. With bringing in a few at a time their choices (probably among others) were to bring people in based on order of preorder or random choice. Either way if you didn't preorder right away, odds are poor for you (one out of what, 2-3 million?) to get in on the first day.