it becomes cost prohibitive to print only a few hundred copies at a time. Not only that, the stores have to be willing to buy them. If only a handful of stores are trying to buy them, then Nintendo has no reason to print them. Don't blame Nintendo for games being out of print, blame the console owners who aren't buying the games and the stores that don't want to stock them.
Either way, you should be able to find any of those games really cheap used, with the exception of Radiant Dawn which still sells for ~$35 used.