If we spend $1T on banning guns and putting anyone who owns one in jail for 30 years (!) there will still be school massacres. Maybe you get 15 dead kids instead of 20. It's still going to happen. That's a lot of money to address something that is very very unlikely to happen. My kid is more likely to get hit by lightning than get killed in a school massacre.
Banning guns because of this is a non-sequitur. You are going to save a couple of lives a year that you actually care about. The media sensationalizes when a rich kid goes bonkers but there were probably that many people killed in Chicago in the last fortnight (Chicago averages a little less than 10 murders a week.)
Gun deaths in the US are mostly related a) self inflicted deaths and
Take a country like Brazil that has much more strict gun laws and way fewer guns per capita. People get murdered just as much as in the US because of drug wars.
You want to address the issues we have it goes way beyond gun laws.