Earlier quoted context omitted.
You say that like no-one would show up to a Paul McCartney concert if Beatles songs were public domain. In actuality, the examples you listed are especially painful because we could be enjoying incredible derivative works based on their music, if not for the stupid way copyright works.
Music is a bad example since the rights system around making covers is incredibly generous compared to other mediums. The fact that just about every Beatles song has a cover in just about every style bears witness to that.
To get an idea what would be possible, listen to the Beastie Boys album "Paul's Boutique", which has been called "The Sgt. Pepper of Hip Hop". It liberally samples all kinds of sources (including Beatles), and the results are amazing, even with that limited 1989 technology. Unfortunately, shortly after that album was released, legal precedents around music copyright doomed any similar works until copyright law changes.