We are not talking about generally intelligent driving systems though. You have to realize that most SOTA self-driving systems are using a lot of NNs. NNs in t

We are not talking about generally intelligent driving systems though. You have to realize that most SOTA self-driving systems are using a lot of NNs. NNs in turn want lots of training data. That training is not fully generic – in other words, if you train a NN using only cameras, giving LIDAR to that trained network (i.e. for inference) will not really do anything. Having large LIDAR arrays on the top of vehicles is expensive and slow to deploy, which directly translates to being able to generate less training data. So if your goal is to have the best possible self-driving vehicles 100 years from now, absolutely you should be using as much sophisticated sensing equipment you can get your hands on, and slowly train your nets for the next century. If your goal is to get out something that is better than a human driver as fast as possible, then it is not clear that requiring all vehicles to have LIDAR on them is the best way to go.