The power draw to process the LIDAR data is negligible compared to the energy used to move the car. 250-300 Watt hours per mile is what it takes to move an electric sedan on average. You might lose a mile of range over an hour of driving, and that's if you add the LIDAR system without reducing the optical processing load.
LIDAR sensor housing can be made aerodynamic.
While it's true that LIDAR was more expensive when they started work on self-driving, it doesn't make sense for them to continue down this path now. It's all sunk cost fallacy and pride at this point.