“Instead of becoming the next Bill Gates or Henry Ford, Kamen might find himself ending up like another great American inventor, Preston Tucker, who in the 1940s built the Tucker, a car too far ahead of its time.”
I think the explanation is far simpler. The Segway revealed what we in the suburbs are getting to know more and more: You cannot walk or bike from any place of significance to any other place of significance in most modern areas of human habitation.
In a world largely created for cars, a conveyance like the Segway is nothing but a toy.
Ten years on, and I've neither ridden one nor seen one at use "in the wild" by anyone other than a mall cop or city tourist.