It also has a terrific permanent collection, hosts amazing world-class exhibitions, and features an enormous art resource library for research as well as a huge art bookstore.
It will be a real loss to Paris and to the world to have this closed for any period of time.
I found it exhilarating and the first time I understood the journey of art from impressionism to today, when artists realized that "Most perfect/accurate representations of reality" (the high water mark reached during of the renaissance) was no longer the way to move art forward. And with the imminent arrival of photography, they were right.
I myself spent 3 decades of my life thumbing my nose at "modern art" with the typical criticisms ("If i can't tell if an artist or a toddler did it, is it art"?)
This museum was the first to show me the evolution of art and I got "it".
I do know exactly the journey that you're talking about in art. It actually clicked for me after visiting Florence and seeing the Uffizi museum's collection of Renaissance art - that's when I realized that there was really nothing more to add in terms of faithful representations of humans and nature after the masters of that time. The increasing levels of abstraction in later movements, from impressionism through cubism to things like Pollock or Mondrian or Chagall - those make sense to me and generate similar feelings as the great Renaissance masters. When I visited a few weeks ago, this was mostly the uppermost floor of the Pompidou, which I loved. I was explicitly refering to this when I said modern art - to Modernism, the artistic current.
However, it's the art that comes after that which I think turned more to grift and self-importance - like most other aspects of post-modernism. Large installations, larger than most paintings or sculptures you'd get in any previous eras, with mostly simple ideas to tell (the whole point of that felt room is the warmth and sound dampening, and it only takes ~50m² to tell its point). Repurposing everyday objects, as if the Dadaists haven't done everything that could be done on this. Lots of self-referential questioning of what is art, or shallow shock value references to topics of the day.
The contemporary collection (mostly on the 4th floor in my visit) reinforced my opinion that the plastic arts are almost entirely a grift today. I'm still hopeful some new artistic current will rise again in the future and come back to creating esthetically pleasing art, even while keeping away from simple representations of nature. I don't think everything that could be said in those styles has been said, but sadly attempts to improve on the works of the 1920s have mostly been abandoned.
[1] https://www.centrepompidou.fr/en/ressources/oeuvre/RqhG4ed
I seem to remember a very similar realization as you, only I thought that was 90% of the museum with only 10% dedicated to "weird spinning abstract structure that is impossible to grok without reading the plaque".
Perhaps I was mistaken!
The one thing I do remember making a shocking impact on me was a massive installation of https://en.wikipedia.org/wiki/International_Klein_Blue. It truly did feel like something imposing and evoked genuine emotion that is impossible to represent on a computer screen.
(The original MoMA was a minor gem and an oasis in midtown. I almost forgave Philip Johnson because of that garden. Now it has lost all its charm.)