I price motor insurance for a living and in my models the absolute worst 'insurable' risks (ones that pass underwriting scrutiny) will have some sort of impact every 3rd year. If we filter that to more severe cases where there's bodily injury it moves out to 8/9 years.

What this means is the absolute worst drivers will go ~100k miles between causing serious accidents so the threshold between good, bad and awful drivers is really far out into the tails of the distribution. Without actual driving data to work from we don't know how safe FSD is and youtube videos are purposefully selected for views. Even so the sheer number and 'randomness' of fails is concerning because nothing like alcohol, speeding or inexperience to point to.