Read over UL's history [0]. It was started by a private individual, and is a for-profit company with huge reach and sets safety standards for devices in many, many industries.

So, while I can't speak to how these things _normally_ come about, this is a compelling example of self-regulation entirely outside of the scope of the government.

[0] https://en.wikipedia.org/wiki/UL_(safety_organization)#Histo...