Maybe you're too young to remember the times before the new gun laws, but in Australia there where similar discussions in the 1990s and in 1996 government decided to make gun laws more strict. And it DID have a considerable effect on the number of mass schootings:
And guns don't really help to protect against assaults if you're not a constantly trained professional. It's just a fantasy that teachers with guns would have gunned down the attacker or those people in the movie theatre could have stopped that gun attacker. It's really just a movie fantasy that in absolutely the most cases doesn't work that way in real life. More guns around in those assault scenarios just open new threats for innocent bystanders.