I thought I read Tesla got away from LIDAR because it won't be inexpensive enough for consumers any time soon.

Not entirely. LIDAR has other issues important when building self-driving cars. LIDAR can't read signs. LIDAR doesn't work well in the rain, though progress is being made these days.. And don't forget the cameras tesla uses don't rely solely on the visual spectrum we see. They can still see through fog via infrared, for example.

Can't the LIDAR eventually be made to use IR wavelengths and thus synthesize 3-d images through fog?

also, the question of seeing the fog is more nuanced that can see/can't see:

"Just like it is impossible to give a simple answer to the question “How far can I see with a thermal imaging camera?”, it is equally impossible to say how much shorter the range will be in foggy or rainy conditions. This is not only dependant on the atmospheric conditions and the type of fog but it is also dependent on the IR camera used and on the properties of the target (size, temperature difference of the target and background, etc)" [http://www.flir.com/uploadedFiles/FOG_techNote_LR.pdf]

LIDAR typically uses lasers in the so-called eye-safe range (around 1.4 micro meters). This range is precisely around the absorption peak of water so that LIDAR cannot damage the eyes of pedestrians and other by-standers. By construction, LIDAR sucks in the fog, rain, snow, etc.

But it has no problems with night. So it has some great uses.

IR LIDAR is already widely used for terrestrial mapping and meteorology. I think if that was the solution it would have already been tried.

Can different LIDARs interfere with each other? I can't see cars using it when all the cars are using it.

The timing is so precise this isn’t a huge issue.

They did, but that decision was a while ago and phased-array LIDAR has come along a lot faster than I think they expected.

Cost/unit was an incredible driver of adoption though. What other depth sensor could you pick up at a local thrift store for $10?