Spoiler Showdidn't you see the chirithi, it's a dream eater, therefore they are in the sleeping world, isn't it awesome to think they will all wake up and then there will be keybladers everywhere, fighting again?
Master Xehanort mentions in BBS that the Keyblade wielders who fought in the war perished, or at least a majority of them. Daybreak Town being in slumber is all just speculation; its true nature has yet to be revealed. Everything's up in the air, especially given the revelation of the "Unchained" dimension, whatever that may mean.
Master Xehanort said:Behold... These lifeless keys used to be full of power--united with the hearts of their masters. On this barren soil, Keyblades of light and darkness were locked in combat...as a great Keyblade War raged. Countless Keyblade wielders gave up their lives, all in search of one, ultimate key. And it will soon belong to me..
20 people hardly merits a war, but Ventus-Vanitas does say something interesting about it.
Venitas said:This X-blade will open a door--one that leads to all worlds! Then, Keyblade-bearing warriors will flock here from each and every one of them, to battle for the light within Kingdom Hearts! And just like the legend says, the Keyblade War will begin!