Interesting! When HN discussed that story a few months ago[1], the common notion was that the driver had enabled autopilot and climbed into the back seat.
That discussion was because the local sheriff's office said that there was nobody in the drivers seat at the time of impact. No idea why they would have said that. Tesla says the steering wheel was deformed in a manner consistent with a person being in the driver's seat when it crashed.
Your take seems a lot more plausible.
[1] https://news.ycombinator.com/item?id=26869962