I see what you’re saying, but it seems impossible to prove it literally cannot happen if you just assume every safety system we put in place all fail at once, which is _possible_ I guess.

We live with worse tail risks daily though: we have nuclear weapons in the center of Europe (could be misused, there could be an accident, etc.), we have labs that handle or create deadly pathogens (there could be a leak, etc.), we live near volcanoes or in earthquake/tsunami prone areas, and of course we are living through climate change with unknown tail risk (to crops, to temperatures, etc.).

If you accept that sort of question with no real probability of happening (“what if 5G renders us all infertile because we misunderstand high frequency radio waves?”, “what if the flu vaccine produced this year kills us all?”), you can’t really do anything. It’s impossible to prove a negative, we have to deal with expected values given our knowledge.