While I totally agree that much of the disrespect is appalling, I believe I have an idea where some of it originates.
First of all, "sir" and "ma'am" is a more regional thing and I've personally always found it offensive.
The Mr./Mrs. thing: Some of us that grew up in the 60s and maybe 70s didn't enjoy being addressed as Mrs or even Ms, and when I divorced the
guy, I sure as hell didn't want to be called Mrs anything. I think many kids grew up calling certain adults by their first name because of divorce or women who didn't want to see themselves as nothing more than a wife.
The rest, y'all know my stance by now. Many parents either overcoddle or aren't present. There are no rules or consequences, in many cases. Hopefully, someone will twitter about that and the rules will change when they're parenting.