I probably don't go back quite as far in my memories as you do, but my experience, from teen years to now, is that music today does have a wider appeal than it did 30-40 years ago. The change has mostly been that older generations are now getting into young people's music more than before. When I was a teen, there was no way that most of my peers would groove to big band music (or even to the early rock of the 50's -- Elvis, Buddy Holly, Pat Boone), and our parents felt the same way toward the "noise you call music". (One exception possibly being the Beatles, as I recall a number of moms back then who enjoyed the Beatles' early pre-psychedelic tunes). Part of being a teen back then WAS the "generation gap": we reveled in our being hip/cool and "nothing like our parents". Our parents would shake their heads and overtly wish that we would come to our senses.
Increasingly during the past 20 years or so, young people's music has been adopted by their parents, even grandparents (the women more than the men). I see the change most pronounced when I attend music concerts. In my teen days, the audience was all young people, but now the places are packed with 2-3 generations of people. You see moms, and some grandmothers, going to see Mylie Cyrus and Taylor Swift and Carrie Underwood. I think there is real motivation -- perhaps spurred by the rapid pace of technological development -- that people today want to stay up-to-date and relevant as they grow older, and to be able to discuss current events and not just refer to "the way things used to be." (like Nat and I do!
To a lesser extent, I also see some younger people going to concerts by "old" acts like John Fogerty, Steppenwolf, Dwight Yoakum, etc. In the local college housing area, one is just as likely to hear speakers on front porches blaring The Doors or Led Zeppelin as Rage Against The Machine or System of a Down.
Not that I think this change is all bad. It does seem like generations today are more buddy-buddy than they were when I was a kid. I think young and older people try to understand each other more now, and to share their thinking on things. There is less "I am the parent. You do as I say", and more give-and-take. The downside is that I believe fewer internal controls and respect for authority are instilled in youth today, and I think that underlies much of the dissension and divisions that we see so much today.
And, yes Blue, I realize I am stereotyping again. But how else can you really come to any conclusions abouty anything if you aren't willing to make some general observations that might not hold true for every person?