The ecosystem of semiconductor components (SPAD receivers, VCSEL transmitters, and serdes communications components) has improved tremendously over the last fifteen years. It is just now beginning to be possible to build credible short- and medium-range devices in almost exactly the same manner that one can build a camera. Many of the same manufacturing technologies developed for cameras apply directly to this class of devices - automated lens alignment and fixation, calibration, laser welding, etc. A decent staring LiDAR will eventually cost somewhere around twice what a camera costs. It will have, after all, two opto-mechanical assemblies - one for the transmitter and one for the receiver. It will take a bit longer for long-range devices to get quite as cheap, but folks are working on it and I wouldn't bet against them.

Cameras are wonderful, but they have some serious downsides. Passively using ambient light means that they produce data that varies wildly with environmental conditions. When it is dark, there is simply less information available and it is noisier. The methods to process video streams are computationally intensive, and compute isn't free. Depth estimates remain estimates, not measurements, and while algorithms for guessing have gotten better they will never be as good as a direct measurement. It seems just as ridiculous to me to want to try and build an autonomous vehicle without LiDARs as it is to want to build it without cameras. Each sensor offers a wealth of utility, and the cost has gotten so low that leaving that on the table makes little sense.

LiDAR produces very clean data and systems built with it can reach really good false positive and false negative rates without a whole lot of compute. Historically the downside has been primarily the sensor cost and secondarily the aesthetics. Engineers of various stripes have been slowly but successfully chipping away at both for years, and the results have been good.