How will/do FSD cars handle 4 way stops? Whichever it counts which cars stop and the order and waits? Car around here don't stop 1/2 the time and 1/4th of the time they go in the wrong order. Or you get people waving you to go when it is their turn.
Waymo is presently operating a fleet of cars that are effectively Level 4 if not Level 5, though they still have a driver in place due to regulations. So there should be information out there that answers your question.
Musk is an intelligent person. I sure hope what he said carry high degree of fact plus some optimism as part of his wishful thinking. To be fair, if the autopilot version 9 can achieve Level 4 (High automation), I will be very pleased for what Tesla has promised.
Based on Level 4 FSD, human driver still be responsible for intervention from time to time. So, it does NOT require government approval. If Must is talking about releasing it by August, it will sure be Level 4 since Level 3 is a "conditional automation and Level 5 will require Congress's approval. I suspect the autopilot version 9 is a complete rewrite of newly simplified (with deeply learning) code based on AP2.5 hardware.
Level 4 is "Eyes off the road." The car is completely self-driving under some conditions, but not all. There will be times when the car parks itself and requires the driver to wake up and take over. It will definitely require regulatory approval, but with the big automakers pushing for it, approval will follow quickly.
Level 5 is a car that does not need a driver at all, ever.
My guess is that we will get Level 4 in 5 to 10 years, and that regulatory approval will follow quickly, due to the political clout of the big automakers. My prediction: It will take longer to get from Level 4 to Level 5 than it takes to get from Level 2 (the most advanced cars today) to Level 4. That's because of the difficulty of dealing with the most marginal situations. I will be very satisfied with Level 4 because under most conditions the car will drive itself without requiring human attention. You can take a nap, and the car will stop and wake you if need be.