The very real problem is that for the past 35+ years, people have been called "kids" or "young", who are long past being either. This, in turn, fosters immaturity and the nation and culture is thusly devalued; as are those words.
I don't agree with what you say there. Also don't agree that "young" equates with (mental and spiritual) immaturity, though one would hope to acquire wisdom and perspective with age. But there is an intuitive aspect to it, and maturity often has more to do with outlook on life than age.
I will agree that as America moves ever leftwards and as the government assumes ever greater responsibility for the lives of American citizens, the citizens become less responsible and less mature as they relinquish their responsibities. Also that this has been a strong trend for 35 or so years.