I also remember making up new toys from parts of broken toys, pretty much combining and mixing up car parts.
I think they have the right idea of customizing parts and shipping them to the end user rather than trying to sell them a 3D printer for the home (like makerbot). I can just imagine a Mattel software that lets you create your own vehicle from 100’s of different parts. You can customize the body, bumpers, wheels, cab, driver, and colors and then have it shipped to you. A week later or a month later you can buy additional parts.