I can appreciate why the lay person may believe them to be similar, but it's hard to express just how much more challenging even the most basic form of driver assistance technology is in comparison to an autonomous vacuum.

The biggest challenge is speed. Just look at the napkin math of detection range of sensors versus stopping distance of a car. The higher the speed, the more range you need... and lidar, radar, etc. all have a fixed maximum detection range.

The rule of thumb is 50m for radar/lidar depending on how much you are willing to pay for the sensor. To stop the car safely, will take 56m at 100km/h.

Then ofcourse, the rest of the struggle is all in exception handling (getting from 70% to 99%).

Comparatively, the iRobot can use the dumbest and cheapest sensors and still be fully aware of everything around it in its relatively slow path of travel. It also does not need to predict the paths of travel of everything around it. It's enough for it to slow down or stop, especially at such low speed. If it hits something or fails to recognise an obstacle, it's not really a big deal. In comparison, lives can be lost in the car and there will be enquiries and legal battles.

I would put good money on the camera based automation delivering the best product at the end of the day, but requiring an order of magnitude more research and development than a comparitively "dumb" lidar setup. The lidar setup will have better immediate results, but probably will never reach the 99.999% effectiveness that everyone is chasing, and will probably never be safe at higher speeds.