Most people have a driver’s license. That doesn’t mean they have a car.
And just because I have an Arizona Concealed Weapons Permit doesn’t mean I have a concealed weapon right now.
Most people get a driver’s license because it’s a right of passage. It is an emblem of increasing maturity and independence. It is an emblem of responsibility.
A pervasive requirement to have a license for a gun would have the same appeal.
Are you old enough? Are you mature enough to handle something that could be used to kill? Do you have the intelligence to pass the written test?
If most people had a gun license, someone attempting to confiscate all guns would have to check everyone because those with gun licenses might have a gun, and those without might have them illegally.
Everyone would have to be checked, license holders and non-holders alike.
Should a law be passed that requires 100% licensing, the pervasive holding of such a license would nullify its effectiveness as a means to confiscation.