There are a decent number of cases of firearms being used successfully in self-defense. It's not as frequent as [anybody selling you products based on that extremely unlikely event of a home invasion] most pro-2A sources would have one believe (2.5million per year is unrealistically high), but per FBI sources that are deliberately low-ball, that figure is around 66,000 cases per year. Not trivial at all, especially when compared to incidence rates of gun violence outside of impoverished areas.
More guns will mean more gun deaths - although statistically the person in most danger of being killed by a firearm is its owner. Accidental gun deaths are the same thing, and that hurts my especially because many of those are preventable. If we're going to be a country with as many guns as citizens, I don't see why a rudimentary gun safety class isn't part of elementary school curriculum (the recommended course basically consists of: Stop. Don't touch. Leave the Area. Tell an Adult), but there exists pushback against that because some people think it would normalize gun ownership (in a country that has 300million guns...).
I live in New Mexico, where the leading cause of death after obesity-inducing unhealthy life choices is death by drunk driver, so I don't even assume the idiots I drive around are sober and insured. Even with that generally low opinion of people who occupy my immediate area, those who choose to own guns seem to actually be less idiotic on aggregate.
In its original conception, the second amendment was predicated on the idea that having privately owned arms would limit power usurpation of the government and keep it as a government 'by the people and for the people', but with the side goal of having additional weaponry available in case we were invaded by a foreign power... but it's not like a foreign army would ever march into the US, and say burn Washington DC to the ground or anything, EH?
There are already schools with those safety precautions in place. Mostly poor areas, and to boot those are really overcrowded schools with poor parental buy-in to the teaching process. Having that widespread seems both dumb and a waste, but there are already areas where pragmatically that has to be the answer.
Guns are efficient tools, though numerically rifles in terms of total deaths (to include justifiable homicide) trail behind things like knives, blunt objects, and cars. No way around the intention of guns as designed, it's to cause damage at a distance, and to do so repeatedly because hitting anything with a high velocity projectile from a tube of steel and crudely installed amount of gunpowder is hard. My answer to anybody whinging about 'high capacity' magazines is to look at the statistics of even law enforcement successfully hitting what they're aiming at (circa 18%), and see if my explanation of how little in a terminal ballistics sense being able to get one or two impacts with a relatively small caliber achieves in a self-defense situation. The practical answer is that most guns are still optimized around hunting, with the side effect of making somebody with one a more difficult target for assault than somebody who is unarmed, so for dealing with the stupidity biased criminal element, they work. In practice, murder innocent and defenseless people can be achieved more quickly with cheaper tools, the only things guns improve for somebody looking to do that is the speed with which one can murder people.
Summary - if you accept the tenet that an armed populace can function as somewhat of a deterrent for anybody with schemes of despotic or even plutocratic rule, then weapons with approximate parity of weaponry with the weapons that would be used by a police state is a requisite. I can't state that is is an apodictic truth, but it's something that the founders of the USA felt so strongly about that the majority chose not to put it into the constitution because they felt it was so self-evident that it didn't bear stating, and added it as the second amendment because they realized how much federalizing aspects of government could concentrate both wealth and power.
There are downsides to this, I won't pretend they're not, but the practical answer is that if law-abiding citizens in the US were the problem, having 300 million guns among them it would be much more noticeable. The problems actually do emerge when weapons amplify the tragic effects of other things, and finding ways to prevent and/or minimize that is hard, but an area where we should be doing better with the tools we have but don't (as an example, the NICS system that should function for background checks is not integrated, is poorly ran and overseen, perpetually under-budget, and isn't easily accessible for private sales - the last one is particularly stupid). A fix there would be tremendously helpful. My answer to school shootings is to add school resource officers, but also enable teachers who voluntarily want to go through a LOT of extra training and screening to be able to extent their CCW permits to their shcools, but that's a small thing not really much of a fix in the big picture. The idea of gun-free zones is silly to me - to put it in MTB terms it's like posting signs and being shocked that bikers would poach trails - but instead of upstanding and overall moral human beings (I presume MTBers to be), we're talking about people already willing to murder others, so keeping law-abiding persons out feels particularly pointless.
Didn't get to ride, but did spend lots of time building racing drones (my other obsession that involves paying too much for nice carbon fiber things that I will subsequently ruin by smashing into things out of incompetence).
As for eMTB's - as long as it doesn't create access issues, those things should be awesome... but as it stands right now they create access issues if allowed onto trails reserved for non-motorized transport. They could share trails with horses, and I live next to an awesome network of trails that are already moto-accessible, but would make an ideal location to ride eMTBs... I just want to take some of the electronic controllers from drones (really similar devices) and fix the overrun issues when you stop pedaling, and manage the specific battery usage through a better P-I-D controller to make it feel more like natural pedaling and compensate for a bike that is running beefy tires.