One big change was that the assault weapons ban of 1994 only lasted 10 years. Congress let it expire. Afterwards, military style assault weapons became the weapon of choice for mass shootings. Quick trigger action and very high capacity magazines allow even poorly trained users to kill and injure a lot of people very quickly. Add body armor to keep the shooter alive, when security forces finally show up. Here is a
List of school shootings in the United States. That page is a rather long list that covers just those since 2000. There is a link to another long list for those that took place in the previous century. Most of these shootings only manage to kill a few people or even fail to accomplish that, but the frequency and lethality have gone up over time as more and more guns with enhanced firepower have become available to the public.
The assault weapons ban did nothing. Fundamentally, it was based on evil looks, not on function.
The firearms makers and dealers rely on looks rather than function to sell their products. Go to your local gun store's website. The front page is splashed with rifles that look exactly like military weapons. They fly off the shelves, but a semi-automatic rifle with the same or more firepower as an AR but has a more traditional look with a wooden stock? That's not "cool." In fact you've got to drill down to find those old, uncool (but still powerful) weapons.
It's all marketing, and I know, because I made ads for a gun dealer. They had the word "tactical" in the name, and their business was mostly in selling rifles that looked like military weapons, and all the "tactical" gear you need to cosplay as a soldier. Tactical vests. Tactical sunglasses. Tactical wallets. Seriously, you can buy a "tactical" wallet.
When I was a kid, a nice rifle was one with quality woodwork on the stock, or a good sight. Nowadays, the kids are sold on how "badass" their rifle looks, and it is worth noting that the perpetrator in this latest shooting was a fucking teenager. So was the one who shot up the store in Buffalo. So was the darling of the gun-nut right, Kyle Rittenhouse. The Oxford Michigan shooter was 15. The Sandy Hook shooter was an old man at 20, and who can forget the teenage Columbine killers?
The gun manufacturers and dealers are marketing these things to fucking teenagers based upon whether or not they look "cool" and resemble big boy weapons. Function? I guess if it looks cool and gets the job done, you get your fifteen minutes of fame for killing fifteen or more of your fellow children.
Now you might be saying "hold on there, Ford...are you suggesting we should pass legislation that keeps companies who make a deadly product from marketing it to children? That seems crazy, and it sure won't work."
Excuse me, but I'm a bit overheated right now and need to take a smoke break...the kids today...they all smoke cigarettes like when I was young, right?