Maybe it has something to do with past loyalty? For instance I have a PC and because of this I never really invested in an Xbox until way after it came out, the reason being is that every game that came out for the Xbox at the time was already out on PC so i went and got a PS2 instead. My sister who had a tons of fun with the Nintendo and the games they release of course got the GBA and Gamecube.

Just speculation but I think people base their choice off of what they like game-wise rather than console wise.