I don't mean this in an overly stereotypical way, but consider the "single mother" (or any other group of adults who are buying presents for children and are on a budget) a $100 console with a huge library of $10 to $20 games is a much more attractive present than a $200+ game system that only has $40+ games available for it ...
This is (one of) the reasons the DS will potentially outsell all other systems combined this holiday season







