If they couldn’t use guns, they’d use cars. If they can’t use cars, they’d focus on torture. i.e. instead of trying to kill as many people as possible, just try to make whoever you catch suffer as much as possible before pulling the plug.
These are all band-aids to avoid addressing the real problem: those who feel they have nothing to live for so they take their anger out on society.
The solution to the problem is reducing the disparity in wealth. It won’t eliminate all of them, but it will severely reduce them. This is why nobody is talking about it. The ruling class has been successful, again, in getting us to squabble over bullshit to avoid addressing the real issue, which is always the money.