I'll disagree with the others and just say "not enough cameras". Cameras alone can work, but you really need stereoscopic cameras in every direction without hug

I'll disagree with the others and just say "not enough cameras". Cameras alone can work, but you really need stereoscopic cameras in every direction without huge blindspots less than 3 feet from the car. Until they fix that, there will be lots of limitations. It could get to be good enough to be hands off a lot more than it is now, though.