That's where I'm not so sure.

Your parallels all strike me as pretty far off-target. In particular, I'm not suggesting we just hope that people's attitudes change. I'm suggesting we actively implement the change via testing, training, benefits, marketing, and so on. Teenagers don't take much of anything seriously, but there's enough ceremony around getting a driver's license that it's hard not to take that at least somewhat seriously. And, yeah, they do kill themselves and others by not taking driving seriously enough, but do you think things would be better if on the one hand had the National Car Association saying that any testing, restriction, delays, or limitations on car ownership and usage is un-American, and on the other, one political party saying that teenagers shouldn't even have cars, and how about we ban them and everyone can take buses, and why do we need big cars like Ford F-150s that ordinary people have no purpose for but inflict worse damage on anyone they crash into, etc.?

We're thirty years on from the Brady Act, and since then the only really significant legislation was an assault-like weapons ban which lapsed after a decade even as mass shootings increased. How much slower can it get?

I mean--it's not like reducing the number of guns can't work. Australia's perhaps the best example of that: many guns removed, tough license requirements, etc.. But Aussies pull together to protect their mates way more than Americans do, they had fewer guns to begin with, the gun buyback was really expensive (the equivalent in the U.S. would cost like two hundred billion dollars), Aussies trust their government way more than a lot of Americans do, and it still was a pretty contentious issue at the time--it passed, and most people are proud of it now, but there was significant opposition.

At some point, it's time to throw up our hands in the U.S. and say, "Look--we can't get the seemingly sane thing done. It doesn't make sense that we can't. It's hard, but looks doable. We've done harder things. But the track record is that we can't, and people are still dying. Let's try a totally different direction, as long as it's the least bit promising."

If "guns are horrible--get rid of them" as an implicit message consistently fails to work, for whatever reason, even if the main problem really is just way too many guns and the resistance just seems like people's stupidity, maybe try "guns are great--a big responsibility but one that thoughtful patriotic citizens can handle". Could it possibly make things worse? For every restriction and check that you add, you place a compensating incentive or perk that's at least as big to demonstrate that gun ownership is respected--it's just the misuse which has to stop.