Conservatives and many other people trust the “free market” to guide people’s behavior in the right direction.
Laws require car owners to carry liability insurance, because if they handle their car badly or an “accident” occurs some person or property is likely to hurt. Liability insurance pays for that. People with bad driving records (many violations, DWIs or accidents) must pay more, according to our “free market” insurance companies, which charge bad drivers more money for their car insurance.
Why not require gun owners to do what car owners must do? Then the “free market” insurance companies would charge higher rates to people who have especially dangerous kinds of guns (assault rifles, etc.) and people who fail to lock up their guns and people who have restraining orders against them and so forth. The “free market” insurance companies could do that by considering prudent risks, without the government offending people who are sensitive about their “Second Amendment rights.”