This is a very interesting story. I lived in that area of Oakland and still subscribe to the neighborhood forum where incidents like this are always discussed. I saw no discussion of any cars going off Grizzly Peak lately and there is nothing in the news that I could find. Usually, a car going off that stretch of road would make the news simply because any recovery effort would require lots of police and fire presence and people would immediately start posting to the forum about the police activity. See, for example,
this story from last year when a car went over the side (and note that the passengers survived, and they were not in a Tesla, so it's hard to argue that the Tesla said your life....)
Also, launching a car on the downslope side of grizzly peak and then having it tumble up to 200 ft down the hill would have left you precariously perched on a slope that would be difficult to climb up in the best of circumstances, let alone after such a horrific accident.
How did you get off the hill and do you have any links to news reports on this accident? Not that I'm doubting you, it's just so odd to not have any news/neighborhood discussion of such an incident.