vtmarmot,
I've thought about what you're alluding to for years. Years ago, you used to be able to buy a gun through the mail. There were handguns with high-capacity magazines. There were no waiting periods or background checks. There weren't mass shootings. So what changed?
Us. We did.
As society has gotten more "progressive" (read liberal)...and nobody can argue that it hasn't...we've lost our moral True North. Behaviors that were unconscionable 50 years ago, are commonplace today. Men, deciding that they're a woman for the day, and using the women's rest room. Bruce Jenner gets a "courage" award for becoming a trans-testicle. We legalize abortion and give an ugly happening like taking the life of a child the euphemism of "choice". This countries tolerance for crime and criminals is appalling. We think people who sell heroin to our children shouldn't go to prison because it is a "Non-violent drug crime" (anybody who thinks the drug world is non-violent has their head up their ass). People who steal others hard-earned property shouldn't go to prison because it is a "Non-violent property crime". We've declared war on our police, accuse them of "systemic racism" but offer no proof, yet won't admit to, or address, the dysfunction in the black community (Can't offend them...have to keep them voting democratic). Those who are smart, successful, and rich are demonized, labeled greedy, and the public is told they are not doing "their fair share" (despite employing God knows how many people, and paying an exorbitant amount in taxes). We are ill-equipping our children for real life by insisting that everybody get participation trophies, and that there are no winners and losers. They never realize that there are going to be people in life that are smarter, better looking, more athletic, are going to have more money, and have the head cheerleader for a girlfriend. And when they "grow up" and encounter real life, they have no idea how to deal with it, get disgruntled, and start assigning blame elsewhere. Or worse. Professional athletes kneel during the playing of the National Anthem in protest of perceived mistreatment and it's "courageous", but when the President takes them to task for it and defends the flag and National Anthem, it's "divisive". If you disagree with the party of "tolerance" on a subject, you are labeled "intolerant", a "racist", and accused of "hate" (The left have "opinions". The right has "biases" and "prejudices". They are tolerant, though...as long as you agree with them lock-step). And, thanks to the left, it has become the era of irresponsibility. Nobody takes blame for their actions. It's Bush's fault. It's Trump's fault. It's the Republicans fault. It's the gun's fault, not the shooter (You see, his mommy didn't hug him enough). It's the rich people's fault. It's the cop's fault. It's "white privilege's" fault. It's society's fault. It is somebody, or something else's fault, never assigning blame to that which rightly deserves it. If you say something over and over, eventually people take it as the truth.
I could go on and on...
That, in my humble opinion, is what changed.
Justin