From the perspective of an archive, library, or museum preservation isn't really the goal in itself, just a strictly mandatory prerequisite. The pieces have to be made available to researchers (and depending on the institution the public) for the archive to be able to consider itself fulfilling its mission.

There is kind of a cost/preservation/accessibility triangle with curatorial preservation, and museums already normally choose storage that is somewhere other than the most expensive/best preservation corner of that triangle. Oxygen-depleted facilities significantly extend that corner, but if we're already not using what we have there then it may not be a useful addition.

Low-oxygen environments also have their own preservation issues. I'm not actually a museum curator so I don't know the specifics. But it is a very complex and old discipline and they've tried just about everything. The problem is usually funding, which unfortunately boils this whole thing down to another boring "you can't solve social problems with technical solutions."