There is a great documentary on Dean Kamen, the inventor of the Segway Personal Transporter, that I highly recommend: https://moviewise.wordpress.com/2015/12/07/slingshot/

My two cents about the main reason the Segway didn't take off is that many people attacked it out of fear that it would take over sidewalks and put pedestrians in danger. It doesn't fit comfortably in a shared sidewalk, or bike lane, or road with all the other transportation options available. And the high cost made it impossible for it to become the dominant alternative transportation form. However, it works well in warehouses and for policing/security.