Waymo, the Google subsidiary, is proving it has developed a completely self-driving car. The company has just held a journalist’s field day at its test facility in Central California. What Waymo hasn’t proven yet is that it can sell the software and hardware necessary for an autonomous vehicle. Its technology is ahead of the marketing. When asked about potential customers, Waymo’s response is nebulous. It might be the company has customers ready to buy when it has declared the technology fully mature. However, two out of three of the major American auto manufacturers have decided to go it alone and develop their own self-driving machines. Waymo could be left with a mature technology and no market. That would be a blow to the engineers who have labored for eight years and tested vehicles for millions of miles. What good is a better mousetrap if no one wants it?