Airbags and seat belts were installed in cars long before they were required by regulators. The same goes for improvements in fuel efficiency. This all is driven by competing companies trying to make a profit.
"A Federal agency today abandoned the longdisputed requirement that automobile manufacturers install automatic crash protection, such as airbags or ''passive'' safety belts.
The action by the agency, the National Highway Traffic Safety Administration, drew immediate protest from safety groups and praise from the automobile industry."
https://www.nytimes.com/1981/10/24/us/airbag-regulation-on-c...