If circumstances should at any time oblige the government to form an army of any magnitude that army can never be formidable to the liberties of the people while there is a large body of citizens, little, if at all, inferior to them in discipline and the use of arms, who stand ready to defend their own rights and those of their fellow-citizens. This appears to me the only substitute that can be devised for a standing army, and the best possible security against it, if it should exist.
https://en.m.wikipedia.org/wiki/Mass_shootings_in_the_United...
[1] https://www.whitehouse.gov/about-the-white-house/our-governm....
Ultimately, you are asking for an amalgamation of these forces to explain the current state of things, and the reality is that only a scholar is likely able to give that to you. The likelihood of such a person existing here is low, so you will likely only get answers from people who don't know the extent of what they don't know.
I certainly don't know the history, but I don't think the history is as relevant as the culture.
I can speak for culture (one of many, my culture) because I grew up in a culture that revered gun ownership. Even as an extreme liberal person, I see gun ownership as a core liberal belief. If someone says they are liberal, but does not also believe in gun ownership, then I think they are a little politically immature. You can believe in gun ownership, but still believe it should be regulated. That is nuance and it's hard to have that discussion. I think a lot of Americans see a simple axiom to their political reality: "guns == freedom". Guns are not just a tool but a symbol.
A core part of conservative (white?) culture is that the government is going to come and take away your rights and if you do not have a gun, they will be taken from you. If you do not have power, then you will be oppressed. Furthermore if you are not willing to sacrifice your life for freedom, then you will not be free.
These are powerful ideas with quotes like: "live free or die" and "give me liberty or give me death," "the tree of liberty must be watered..." "freedom is never given, it must be taken" "better to die free than live a slave" "if you want peace prepare for war" "if you give up freedom for safety, you will get neither."
These are not idle ideas, but ideas that shape our understanding of reality.
So when people who grow up in this culture of gun worship hear the message "we want to take away guns from the bad people," what they don't hear is any nuance or depth or ask if there are individuals who should not have the right to fight oppression, what they hear is "I (the government) want to be able to oppress you, so I am going to whittle away your rights until you can't fight back." That isn't an exaggeration. That is the message that is heard regardless of how the idea of gun policy is expressed.
"Political power grows out of the barrel of a gun" is a famous communist quote, but it is very true. American culture says that the people must have power and therefore people must have guns. Guns are the tool of last resort to use to fight oppression and as free people we must have access to those tools to fight it.
Sadly, guns are a tool to execute power, and power itself is amoral. Power can be used for bad and for good. In America this power that we have been granted is being abused in ways that it is obvious on the world stage. Our culture clearly has a sickness.
We frequently talk about freedom, but fail to talk about responsibility to use our freedoms properly. "Rights" framed discussions rather than "responsibility" framed discussions result in what we see. Abuse of rights without any way to address neglected responsibilities creates an environment where the rights themselves are called into question.
Many genocides have been committed through first disarming the targeted population (Armenia, Germany, Cambodia etc). Committing genocide on an armed population is orders of magnitude more difficult compared to one that is unarmed.
It's easy to say it could never happen where you live, but things tend to change. And if/when they do it's not like the government would start easing up on restrictions. I don't see that ever happening. You need to have it strongly in the constitution for it to actually work.
Self-defense is what most people seem to be talking about and that's certainly a use case, one which becomes more important the further away from the nearest police station you live (or just in crime-ridden neighborhoods). But while this is the most popular talking point I don't see it as the most important one.
With regards to mass shootings, they aren't really that common when you factor in the amount of firearms there are in circulation and how pretty much anyone can get an "assault rifle" (which seems very difficult to define by those advocating against them).
Homicide rates aren't crazy either but obviously there's a flipside to everything and having more guns in circulation will statistically increase their use. But it needs to be weighed against their ultimate purpose and benefit - freedom from oppression. This is the main reason so many people fled from Europe and came to the US in the first place. And people are talking about removing that now just because of a small amount of shootings? There are orders of magnitude more homicides with hand guns compared to the mass shootings. If you honestly care about people dying from then then, well, yeah, you can argue for government regulation and buyback of most firearms. But you would definitely focus on hand guns foremost.
But that also brings in uncomfortable stats which show that black people are disproportionally responsible for homicides in the US.
And then look at suicides. Even though it's super easy to kill yourself with a hand gun you have higher rates of suicide in many countries with very strict gun laws.
I wish there were more examples of countries with similar constitutions. Mexico I think has a constitutional right to self-defense in your home but the culture is quite different there.
As opposed to most countries now which seem to center more around the government, the US has historically been about the people. The whole idea of the second amendment was so that the people would be able and willing to defend their property (also a strong part of the constitution) and thus homeland without relying on the government for it.
tl;dr: Of course having relaxed gun laws comes with more accidents and more violent crimes (statistically speaking). However the way most of the western world is centering in on nanny state -like policies I'm increasingly getting convinced that the US constitution was and is on the right track. People can self-organize and be responsible. A larger problem in the US nowadays is the lack of a cohesive social structure. People feel alienated. This is moreso what leads to shootings, not guns themselves. Gun restrictions (in whichever form) would be like applying band-aid - while they would decrease firearm incidents they would also not do much for the actual bottom line, however much gun control advocates would want you to believe.
And then we're not even talking about practical issues. With what, half a million guns in circulation any buyback program would be futile. Australia did one and managed to reel in 1/6 of the targeted firearms IIRC.
So even if politicians/activists were honest and said that they wanted to ban all guns for everyone, eventually, I don't see a sane path towards that. And despite that they just keep on chipping away things bit by bit, with the intent of "making the world a better place", while mostly ignoring that gun rights were (and are) backed by a very clear purpose.