In the Time article, Kamen says, "it makes no sense at all for people in cities to use a 4,000-lb. piece of metal to haul their 150-lb. asses around town." And he's right, just ask the Dutch who ALL OWN BIKES and actually use them in their every day lives.
Personally, I can't stand Razor foot powered scooters, and I imagine I'll be annoyed by the folks who will be using a Segway (for being rich enough to afford the $3k price tag ;)