I said one of the reasons. They probably did some cost analysis and realised it's not worth spending engineering effort on other modes when human drivers are able to drive around pretty much using only vision.

I didn't say it was the only reason. Re-read my comment.

> They probably did some cost analysis and realised it's not worth spending engineering effort on other modes when human drivers are able to drive around pretty much using only vision.

Humans and cars aren't equal so this is just incredibly misguided as a principle.