I know that automotive parts of the standard requirement to withstand 80°C (or 120°C for military use). A robot vacuum working in a living room can probably be made cheaper because it does not have to face as harsh environments?
Also, range is probably a factor. In a living room, you probably need something like 20m max. You car should "see" farther.
Not only that but vibrations play a big part as well, especially on ICE vehicles.
Sure, these are the assumptions but silicon is silicon, copper is copper and solder is solder. They don't use easy melting electronics in vacuums and hardened stuff in cars, the tech is about the same unless it is supposed to work in highly radioactive environment. The plastics are different but car interiors are full of plastics, so its unlikely that the costs of temperature resistant plastics needed for this is more than a cupholder.
As for the range, again pretty powerful lasers are sold for sub 10SUD prices on retail. I am sure that there must be higher calibration and precision requirements as the distance increase but is it really order of magnitudes higher? 120 meters laser measurer with 1cm accuracy is 15 Euros on Temu and that thing has an LCD screen and a battery as a handheld device. How much distance do you actually need?