I think where I come from, one factor has been the increasingly weak social shaming / enforcement.

Back when I was a kid, if you put your shoes up on the seat opposite you, you could count on some old lady telling you off and telling mom that she didn't raise you right.

These days, everyone keeps to themselves and I believe that lack of social enforcement leads to a worse society. Tell people when their behavior is unacceptable. Don't just let the standards for what you can get away with decay.

Personally, I still call out people playing loud music or using speakerphone. Of course, as a tall, broad-shouldered man, I am in a privileged position to do so, but y'know, gotta lead by example.