Cars have a useful purpose, guns do not.
You don't consider the ability to defend yourself against an attacker to be a useful, valid purpose?
Note: The main historical reason for keeping weapons away from a people or people group was to ensure they could never rise above their 'betters'. It wasn't just applied to guns; consider that a peasant found with a sword was likely to face severe punishment, if not death, in most of medieval europe.
Those who hold power, or those wishing to do so, will do their absolute best to ensure that others, those outside the 'in' group, will be unable to defend themselves when the time comes. It's written all over history.