Because the additional cost is worth it when lives are at stake.
Cost doesn't mean just mean money. Government oversight creates significant friction and there needs to be a very good reason to accept that friction into an industry. Risk to human lives is one of the few things where it is sensible to introduce that friction.
Government are there to prevent friction for its citizens, not for faceless entities.
>Government are there to prevent friction for its citizens, not for faceless entities.
Have you ever tried to get a safety critical system certified by a government authority?
Public safety is an externality. The air and water are externalities.
Private industry can't effectively compete to optimize a cost which is not "priced in". That's the whole point. If you can pollute, damage public safety, et al, it amounts to a free subsidy, you are externalizing costs which should show up in your balance sheet.
It's like people read Ayn Rand, or some cliff notes version of free market capitalism, but don't read any of the deep philosophical economic arguments in the literature, and then parrot slogans around.