My impression is that the majority is fine with the profits due to sales of assault riffles and bump stocks being lost. And the majority seems fine with some additional expense being associated with gun purchases as a trade off against the benefits of uniform background checks and gun laws. Just my personal impression of what the majority favors, your impression my be different. The idea that we should be armed to the hilt for the time when the Guberment shows up at your front door in an Abrams Tank has some appeal to the lunatic fringe of society, but it's just looney tunes to most Americans. It's a no sell to the majority, Sorry.There are several flaws in your post you continue to ignore.
First, the argument about how other countries have done it. No other country has the amount of firearms in circulation - both legally and illegally that the US has. Not. Even. Close. This is an important distinction in the idea that you can limit the problem by controlling the future number of firearms in production. That horse has left the barn long ago.
Second, your argument that you can reduce the probability of future events by restricting firearms. Can you reduce this probability by some statistical amount? Sure. However, the issue is at what cost? If you tell me you can reduce the amount of car accident fatalities in this country by half by eliminating all travel and forcing everyone to stay at home and cyber commute everywhere, then I (and many, many others) would tell you that the restriction on our liberty is not worth the added "safety".
It all comes down to that. If you restrict the purchase of handguns (as an example), the small improvement you will see with handgun crime (and it will be very, very small because the crime is committed by those who already illegally own handguns) is not worth the restriction to the vast majority of citizens who legally own and legally use these handguns.
There is no restriction on your Second Amendment right by any of the Kid's proposals that have any traction. So we can simply dispense with any argument based on unreasonable restriction of liberty. The Constitution, as interpreted by the Court handles this issue nicely.
I'm afraid that your observation that there is already so many guns in the U.S. that any restrictions will have only minimal effect is going to fall on the deaf ears of the majority. But you can keep trying out that argument until proven wrong. And you will be, of course. Because the distribution of guns among the population isn't even close to uniform. A fraction of the population owns the majority of the guns, invalidating your argument.
These kids are going to succeed where adults couldn't. They are going to send those congressmen who refuse the will of the majority packing come November. Most likely they will have the congressmen so scared come Summer that by November we will have sane, effective, and uniform gun laws in place. But it doesn't really matter, because if we don't, then come January we'll have a whole new Congress. And that Congress will pass gun legislation. So either way, it's a done deal.
Finally consider this. The reason we don't have reasonable gun controls uniformly enforced across the entire country is because of money paid by the gun lobby to keep profit impacting gun legislation from been implemented. The lack of reasonable gun control laws has nothing to do with logic or loss of Second Amendment Rights, it has to do with money. The kids from Parkman have figured that out, and they are going after those who have taken the money.
In a perfect world there would be no laws. That would require perfect people. A person who values their personal freedom in the imperfect world we live in will equally value good and sane laws.

