Waymo put a ton of sensors, including lidar and cameras, to create a truly driverless experience. Tesla put a ton of cameras to make a mostly driverless experience (but when you need a driver you NEED a driver). Comma strapped a cellphone cam to the windshield to make a semi driverless experience on straightish roads, and a driver must take over when anything complex happens. Source: very happy comma.ai user for many years now

Waymo basically prioritizes accuracy of surroundings. This is why they started to operate only in certain areas after mappings have been completed. Then within those surroundings they do a mix of things including ML reinforcement learning for behavior as well as optimizations in terms of route planning.

Tesla on the other hand basically went on Musk infinite wisdom and said "humans only need eyes to drive, so we are going to do cameras only". Their methodology is essentially end to end - i.e take a sequence of frames, and train a model to predict where the car is going to go based on human driving data.

Comma Ai basically followed Tesla, except they did so with a much more hacked together approach. Their final product is good, but there is a reason Waymo is winning.

Geohot, holding the title for being #1 simp for Musk, of course subscribed to that philosophy.