@Blargh True. But he COULD change his mind, that's why people are arguing.
I suppose another reason for allowing all three (as LuckyPokeGirl sort of brought up) is that a lot of people will be wanting to join the three games that are left, which will either create a very long waiting list or cause possible confusion. Either case is not good. With one more game, there are more games to join, meaning less of a waiting list to play the games, thus creating a more efficient Game Corner.
And these are the most popular games, just because you let one more game in doesn't mean you have to let in another. It's not like any of these games have unintelligent, YPPY posts. It's not like it will make Pokebeach a worse, less intelligent place. All in all, it won't hurt (but I understand it could push activity in other parts of the forum down). The benefits outweigh the cons.
And it looks like I'll have to recant my previous statement that MM will lose. It's tied with The Challenge right now.
EDIT: Super ninja'd. I'm not complaining, I suppose it is true we could've had no games at all... well, it's your choice, SR, and I know you know what's better for the site than we do. Never mind what I said haha