

LIDAR generally works better at relatively short distances (like less than a km). Several other car companies are going with LIDAR and do alright. Musk thinks cameras with image recognition would be sufficient without anything else. It goes without saying that Musk is very wrong.
Prices tend to come down on these things simply because the car industry widely adopts them. For example, accelerometers became cheap because they were needed for air bags. LIDAR might not come down as much as those have, but it won’t be tens of thousands of dollars.