Subject: Re: Sgt Pepper
Today I play in a small jazz combo, mostly playing standards from the Great American Songbook.

Well, sure. As we get older, we learn more and have more awareness of stuff that came before us. But as you point out, when you were a youth that wasn't really on your radar.

It's not surprising that someone in their 20's isn't necessarily familiar with the second tier of the major artists from fifty years ago. If that person decides to pick up guitar later in life, I fully expect they'll know who Santana and Clapton are.