In reply to the kids not owning a GameCube:
I think the price won't help either way.
From what I hear, most kids under the age of 14 or 15 won't buy a GameCube because it's kiddy. My parents are very, very strict (my mom starts sweating when I ask for a M-rated game), but even I got away with Halo, and even DOA: Xtreme Beach Volleyball.
2nd) When kids see "Xbox - $150, PS2 - $150, GCN - $100", they're going to think the reason the GCN is cheaper is because it's a less powerful console/ it's not doing very well.
Above everything else, kids want to do what the "adults" are doing. They think adults are buying Xboxes (which isn't true from what I've seen, most gamers over the age of 18 have a PS2 and many have a GCN).
Of course, where I live price is rarely a concern. So maybe in "less-fortunate" neighborhoods, they will start buying a GCN once it goes under 100.