For example, Hans Haacke had a piece which was literally documenting the provenance of a museum's Manet painting to reveal a connection between the donor and the Nazis. That's literal, but I hope most here would think it's not at all superficial.

Exit Through the Gift Shop remains integral to our moment. https://en.wikipedia.org/wiki/Exit_Through_the_Gift_Shop

The Science Museum in London still had Maudslay's lathe on display. Maudslay's lathe is the direct ancestor of all modern lathes, with its slide rest and the leadscrew drive. No previous lathe was like that. So it's one of those rare artifacts that changed the world. People walk by it to get to see James Bond's car. That was the strength of that museum - they had some of the first examples of key advances.

The Henry Ford Museum used to have really obscure items. "Capacitor, Cornell-Dublier, 1938". A combination television camera and kinescope projector for rotating disk television. Then they added explanatory exhibits and pushed aside the small obscure stuff. That was probably for the best; it was like a really well funded antique shop. The kids just want to see the locomotives, anyway.

The Smithsonian was once called "The Nation's Attic". Now, most of the obscure stuff has been moved out to storage in favor of more understandable exhibits. They used to have a history of clock escapements, with a working model of each type, kept wound and running. No more. The Arts and Industries Building had even older stuff. Their stamp collection had examples of all US stamps.