Personally as much as people like to dunk on Musk, he did build several successful companies in extremely challenging domains, and he probably listens to the world-leading domain experts in his employ.
So while he might turn out to be wrong, I don't think his opininon is uninformed.
His autopilot has killed several people, sometimes the owner of the car, sometimes other drivers sharing the road. It is hard to root for this guy.
I fully agree with your first point: Musk has shown tremendous ability to manage companies to become unicorns. He's clearly skilled in this domain.
However, if you think about this for 2 seconds with even a rudimentary understanding of sensor fusion, more hardware is always better (ofc with diminishing marginal value).
But ~10y ago, when Tesla was in a financial pinch, Musk decided to scrap as much hardware as possible to save on operational cost and complexity. The argument about "humans can drive with vision only, so self-driving should be able to as well" served as the excuse to shareholders.