I don't know what exactly Musk said on the topics you raise, I only know that he did say something like vision being the core problem and that lidar can't solve that problem (nor can any combination of other sensors we currently have). It makes sense to focus on vision and to question the value add of lidar, because if you can solve vision then many other sensors are redundant.

Maybe it can't be solved using current tech, who knows, but saying that fully autonomous driving in our current world isn't achievable without vision is a correct position. I have no opinion on anything else.