People really need to get this through their heads -- games in Japan generally only usually get 2-3 days of sales their first week.
It's like saying a movie didn't bomb because it only opened on Friday and that's only three days worth of ticket sales. Almost all movies open on Friday.
It's been done this way for almost 24 years now in Japan after the Super Famicom launch caused near riots at some stores (oh, how far Nintendo consoles and consoles in general have fallen since) during a weekday, the Japanese government asked game makers to schedule game launches on the weekends so kids wouldn't skip school. So this isn't a new thing either unless Home Alone and Die Hard 2 are "new" movies in your book.
The bulk of most games sales are in the first 2 days and most games only get 2-3 days in their "first week". Super Smash Bros. 3DS also launched on a Saturday. So did Pokemon X/Y. Most Nintendo games launch on a Saturday, a handful of (usually Mario games) they allow to release on Thursday. That's it.
38k opening for a game is not great. In virtually any circumstance unless there was some freak issue like a tsunami or massive shipping issues, neither of which are the case here.
