Most of the art in museums is long past the copyright date. This includes many artists who are considered "modern". Works by Picasso, Marcel Duchamp, Henri Matisse, M. C. Escher, Max Ernst and Constantin Brâncuși are some found on the recent lists of art entering the public domain.
Originally copyright was 14 years with the option to extend another 14 years if you registered your copyright. That seems a lot more reasonable to me, no idea how we ended up with 100+ year copyrights.
