You’re very fond of assuming that the car DID brake. There’s nothing to indicate that in the story.
I’m assuming nothing. Maybe it braked, maybe it didn’t. Maybe it had an opportunity to brake, maybe it didn’t. We don’t know, and frankly it doesn’t matter. What we know in this instance is that whatever went down the human backup didn’t spot it in time either. Which happens. We live in an imperfect world. You want to make assumptions and play the luddite, but out here in reality all the current data says a human wouldn’t have done any better (because they didn’t).