[Someone]

Yes, the problem is difficult and hasn't been solved yet. Knowing that, Tesla should have figured out how to safely disengage autopilot and transfer control back to the driver before selling this feature (an autopilot in a plane, for example, can alert the humans in the cockpit way in advance of upcoming problems, and has incredibly annoying ways to get their attention, if needed)

I saw a tv program about self-driving cars a couple of years ago where the programmers said they would have it ready for major roads in a couple of years, but their human factors engineer said "a couple of decades", precisely because they realised humans would always be needed, and that the problem of transferring control back to humans while riding on the road hadn't been solved.