There has been a culture shift going on in regard to values and morality.
When I was in high school it was no big deal to see a rifle or shotgun on a rack in a pickup truck in the school parking lot. Not anymore.
When I was in school kids didn't get in trouble for sex on school buses, in the bathroom, etc. Yeah, copulation was happening, but not like today's abandonment of any sense of shame.
Back in the day smoking dope was a big deal. Now Meth and other drugs are everywhere. They're cooking it in the hollers of West Virginia and trailer parks all across the country.
We are reaping the harvest from decades of negligent parenting. Kids dominate and manipulate their parents at a higher rate than I've ever seen. Many kids aren't taught right from wrong, and the consequences of making bad choices, then grow up to be adults with no concept of how to function as part of an orderly, civil society.
Many people mistake MTV crap for real life. They think wearing a baseball cap sideways and a Mercedes-Benz hood ornament around their neck while waving a Glock fo-tee around actually impresses people.
I'm originally from north-central PA, and when I lived there, I'd say there was one murder every five years on average in my community. Now, who knows? I haven't lived there in years, but I imagine it's following the trends you describe.