The oxidation is what's keeping it together, if you clean the oxide off and don't seal it then it oxidizes again and takes material with it. It's similar as to why stainless lasts so long.
The issue is you need to recoat sealants every 10-15 years, you only need to chat oxide every 50 to 100 to access damage and most of the damage is on the internal iron structure that the dielectric force is slowly eating at a faster rate then the copper skin.
There was a bunch of news about it around iirc 1980 when they cleaned sections to rebuild the inner scaffold in some areas.
I mean, isn't that kind of symbolic though? France does regular maintenance on their democracy, we wait until it's on the verge of irreparable corruption before we (hopefully) go in and fix it before it collapses