In The London Rock And Roll Show (1972 oldies festival at Wembly Stadium filmed by DA Pennebaker, I think), Mick Jagger said "I wouldn't think anybody would want to come..." to see older bands like Bill Haley, Bo Diddley, Screamin' Lord Sutch, Jerry Lee Lewis, Little Richard, and Chuck Berry.
Full concert on youtube.
http://www.youtube.com/watch?v=i_0l1zxNeKg
When an oldies festival was booked for Toronto not even a month after Woodstock, they were worried that there wouldn't be enough tickets sold so Kim Fowley told them to get a Beatle. I don't think John was the first choice but it was the debut of the Plastic Ono Band. The concert also had Jerry Lee Lewis, Little Richard, Chuck Berry, the Doors, Alice Cooper. I am not sure if Gene Vincent was a part of this or not.
DA Pennebaker filmed this one as well. Here is Jim Morrison (who's band the Doors had already played at least one other concert with Jerry Lee Lewis) expressing gratitude for getting to share the same stage as the older performers who he grew up on.
http://www.youtube.com/watch?v=N0ewoypJQUI (the film may or may not be from this concert, it certainly is not synced sound).
To the boomers (audiences, not performers!) in 1969, nothing existed prior to the Beatlemania. The career drops of the performers I mentioned was sudden when it happened around the Summer of Love. They were, and then they weren’t, even though Warner Brothers Records under Lenny Waronker, if memory serves, put out great albums by Fats Domino, Little Richard and Everly Brothers, and Chuck Berry returned to Chess for one really good album. None sold, all were forgotten, until the younger performers themselves dragged them out into the spotlight a decade or so later. Think Roy Orbison, or the Everlys’ McCartney written last hit.