I think it is more a general decline in society, than a generational or age thing. Contrary to all of the social media outlets, society in general is less "social" and more self-absorbed. I'm not a big Facebooker, but I see just as many selfies from "kids" as I do from folks my age and older. I also see the rudeness across the age spectrum as well.
Personally, I try to never respond to rude behavior with rude behavior. If anything, I try to be more pleasant and nice. It is like wrestling a pig. You both get dirty and at some point, you realize the pig is enjoying it.
The kids and I have discussions about rude behavior and not thinking about others as you are going about your life. I'm hoping I can at least have them be respectful of others. I guess time will tell if I'm successful.
In a timely fashion, I was behind a driver in the drive thru at a local fast food establishment. When they got to the window and got their food, the driver pulled up about 3 feet and then proceeded to pass the food out and get their child situated in his/her car seat with their food. Of course they are still blocking the window. I just shook my head.