PERSONALLY: don't see any way or reason for it to change. It is the human nature, biology, some percentage of the population will always be crazy. Some of them will be very good at hidiing it. Violence is nothing new. It may ebb and flow. but overall consistent with population.
As previous posts indicate, the worst school attacks occurred decades ago and involved explosives, which have been around for thousands of years.
As to gun violence, what's that? How about knife violence, China, pipe bomb violence, Unibomber, etc. its simply convenience violence. Sometimes personal fantasy violence. Limiting access to guns does nothing to limit crazy. I submit, nothing will.
Walk on the other side of the street, figuratively and literally. With a gun.
Or so I think.