Shooting people with a rifle is not scalable and there is a high risk of getting caught. Imagine if school shooters could kill thousands instead of dozens, and at zero risk.
The school shooter type seems to want to be present locally, to go out with a bang, and to do it somewhere they are connected to.
They are not aiming for maximal scalability nor chance to get away.
Of course, other threat actors might, like a Unabomber type or groups designed to destabilize society (perhaps foreign sponsored) by doing repeated actions etc.
