I don't get why people think this is theoretical. We have autonomous vehicles driving on the road _today_. They've logged millions of miles. The question is one of fidelity. Can they drive "safe enough?" Can they drive in a blizzard? These are important questions and are needed to answer a question like, are autonomous vehicles "sufficiently advanced" enough to fully replace human drivers in most scenarios? But even if they never advanced beyond what we have today, they still would have use cases that demand clear regulation.