What I know (or at least I believe is true):
A huge number of families in rural America hunt for some (if not most) of the meat their family eats in a year. Trying to change a gun culture that is still a part of a family's sustenance is never going to happen. You can never convince that family that their guns are bad. Their guns feed them.

For the weekend target shooters, they do not ever keep their guns unlocked or near ammo except when they're at a regulated shooting range. They're not going to understand how their behavior is in any way a threat to anyone, and will not be swayed into teaching their kids that "guns are bad". They have probably already bought their kids their own guns to go shoot at the range with them.

For the guy who has gone through every required safety course and carries a gun everywhere he goes, changing his mind is laughable. He almost definitely owns a number of illegal weapons, is likely ex-military, and holds his guns with a reverence that will not falter. His guns are a huge part of his identity.

My opinion:
These 3 groups alone are large enough to keep the gun culture in America at a status quo. I can't conceive of a practical way to "changing the gun culture in America by teaching the kids". It could take an outbreak of vigilantism (or outright rebellion) on a national scale and the fallout and resolution of that conflict to change the way American's perceive domestic gun ownership.