"... How else would we get to see the Beatles or Buddy Holly live? ...

We are not getting to see them live. We are getting to see a tribute act. "

Also, rest assured, if The Beatles, Buddy Holly or whoever were touring today they would either be playing new material or interpreting their old songs differently. It's very seldom that live bands faithfully reproduce their own hit singles note for note. Not the more imaginative acts, at any rate.