Actually about 40 years ago we started closing mental institutions and putting the dangerously mentally ill out in the community.
Morals probably play a role as well, but the problem is mainly that we allow the known dangerous lunatics to roam the streets.
“...about 40 years ago we started closing mental institutions..”
When a bureaucracy(fed, state or local) is told must cut its budget, as Reagan did, the first things cut are the essentials that will damage the public.. budgets of schools, police departments, etc. This is punishment for daring to trim the sacred cows. The lard is cocooned and protected.