Because Elon is a scam that wrongly voted for vision-based technology and can’t back out of it without losing money.

We manage to get away with 2 2D sensors, that can actively move around and we have freaking 3 billions of neurons with extensive knowledge of the physical world. We are not giving back only a 3D approximation due to the angle difference between our eyes - we also semantically analyze it, knowing what a car, a tree, the sky, etc are, with their usual dimensions in directions where we don’t even see it.