Well it's not completely clear to me that cameras can't look a few cars ahead. If we can, cameras can too. Maybe they're not smart enough yet, but I don't see the fundamental limitation. Apart from that, I agree that cheap + effective LIDAR would help significantly to get autonomous vehicles on the road now.
A camera is not a replacement of how our eyes work, how our brain distinguishes between objects and understand from prior experience and can make independent decisions on the fly.
But neither does LiDAR, but with LiDAR and good machine learning (ie, Waymo), you can drastically improve the reliability of your autonomous system.
Elon is insisting on a no-LiDAR system at the same time advertising tesla autopilot as an autonomous system and has said multiple times that All Tesla on the road is already equipped with the hardware needed for fully autonomous driving. This is dangerously false.
There is not a single autonomous car out there (at least serious ones that we know of), that has a non-LiDAR system.
Reality Distortion Field is strong with Elon, Unlike Steve Jobs and Apple products, this one will kill people.
So I do a lot of work with both vision and lidar data, and am pretty intimately familiar with the public state of the art in terms of perception systems that rely on each or both, if not planning.
I don't think you need lidar.
I'm not saying that vision-only won't take longer, because it will, but I believe it'll probably happen unless the cost of lidar falls a great deal.
Have a look at, for example, "learning to see in the dark" (the CVPR 2018 one), DensePose (the FB research one) to get a sense of how quickly difficult problems are being solved.
I don't think it's a cost, Elon has a personal bias, or maybe he didn't account for the fact that in the not so near future LiDAR cost will go down drastically.
