I'm not advocating switching over the visual only, unless the other sensors are broken or unavailable as you describe. I'm just advocating we do the research,

I'm not advocating switching over the visual only, unless the other sensors are broken or unavailable as you describe. I'm just advocating we do the research, create some visual-only cars as proof of concept, solve those thorny AI problems. It's an artificial constraint, one which will produce engineering innovations which can then be applied back to real world products.