Even if they could: Why settle for a car that is only as good as a human when the competitors are making cars that are better than a human?
No part costs less, it also doesn't break, it also doesn't need to be installed, nor stocked in every crisis dealership's shelf, nor can a supplier hold up production. It doesn't add wires (complexity and size) to the wiring harness, or clog up the CAN bus message queue (LIDAR is a lot of data). It also does not need another dedicated place engineered for it, further constraining other systems and crash safety. Not to mention the electricity used, a premium resource in an electric vehicle of limited range.
That's all off the top of my head. I'm sure there's even better reasons out there.
> Lidar can be added for hundreds of dollars per car.
Surprisingly, many production vehicles have a manufacturer profit under one thousand dollars. So that LIDAR would eat a significant portion of the margin on the vehicle.But LIDAR would probably be wired more directly to the computer then use a packet protocol.