I always thought it came down to two reason, costs and looks. Telsa has to sell a car people want to drive daily. They can't have a bunch of lidar sensors on their cars no one would buy them even if they could drive themselves. Also they would most likely cost a lot more due to lidar sensors not being cheap compared to normal cameras.

Unlike Waymo who doesn't care about selling cars to people to drive daily. No one going to care that the taxi they are taking looks ugly as long as it get them to the place they are going for cheaper. The cost is also a less of a factor due to them being able to produce an income by charging people to ride in them.