Earlier quoted context omitted.
I haven't been in a car accident for 15 years, not even fender benders, that doesn't mean I shouldn't take insurance. As someone from a random developing nation car accidents deliver crippling debt and destroy lives there frequently because insurance is not mandatory. The developing nation blindly ignore the externalities of not having insurance (instead of spreading the cost throughout society, only a few people bea…
It comes down to the amortized cost of insurance vs amortized cost of not. Say nothing about how incentives get fucked all to hell by breaking things across many parties (principal agent problem) and the money distorts things. And this isn't just insurance. Just because someone who work is being made for by law or by rule says that their work output reduces the failure rate from X to Y doesn't mean that the cost of t…
Examples: Leaded gas, tobacco, CO2 emissions, dam breaks, reactor meltdowns, air pollution (really pollution in general; river/groundwater contamination for your septic tank example)...
If you underregulate, you end up with frequent cases where not even imprisoning and dispossessing everyone remotely involved/culpable is gonna get you sufficient compensation; this is extremely undesirable.
Companies are frequently gonna steer towards such scenarios, too, because they can allow them to externalize costs.