Instead of betting on RADAR and LIDAR HW getting better and cost going down, they went with vision only approach. Everybody in this field knows the strengths and weakness of each system. Multi-modal sensor fusion is the way to go for L4 autonomy. There is no other way to reduce the risk. Vision only will never be able to achieve L4 in all the weather conditions. Tesla may try to demonstrate L4 in limited geography and in good weather conditions but it won't scale.