Christmas also isn't as big a deal in Asia as it is in the western world.Why does Japan get the PS4 last ? Simple.
Sony doesn't have an unlimited stock of PS4s so they want to sell as many PS4s in countries where the Xbox usually does well or not too bad before the Xbox one is out. The Xboxes historically don't sell well in Japan so there is no need to beat the Xbox one's release date in that country. It's clever business.