Elon may not be a great engineer but he is a genius businessman in many aspects so that would also make sense.
To a layman the sole reliance on cameras seems like one of Tesla's biggest mistakes.
This is quite subjective. My opinion is not very representative, but I for one find teslas horrifically bulky and ugly (and most other cars, in fact). They all look like gigantic broken eggshells. On the other hand, a lidar rig looks very cool.
There is no reason to not to have them in a car priced $100k, even just as a failsafe backup to the videocamera.
In the future though, mass produced single chip radars have all the chances to beat every other sensing method on cost.