Every librarian I've ever spoken to has been incredibly good at pointing me in the right direction if they didn't have anything in the local library. They understand the need for archival, but they are also limited in space and money and need to focus on what their typical users actually read.

If you can't find something, ask your librarian where it might be available. Generally they can give suggestions, and may even spend time helping you search.

In my teens had libraries contact specialist libraries and dig obscure translations of works out of vaults for me where they could have just told me sorry and pointed me to the several newer/more mainstream editions of the same work they had out (I was transcribing some books where the newer translations were still in copyright and where I was also hunting for additional forewords), despite being young enough at the time that they could've easily dismissed me as not having any "important" reasons to trouble them with asking for just those editions.

My experience is that if you're nice, most librarians love it when they are asked for something unusual by someone who clearly cares about the books.