I understand not having maintainers for actual bug fixes of tricky things. But the "maintainer disappearing" scenario has almost always been just for keeping things running. And in particular people show up with patches! Just well... some arbitrary person was a maintainer, is no longer there, and now there are bunch of people who would love to do most of the work.
I think that "lack of succession strategies" is what really gets these packages, rather than the lack of willing maintainers. Combine that with deep dependency trees and you have a lot of stuff that needs to happen.
I get it though. And I maintain some packages but I don't get involved in standard library shenanigans cuz my imagination is there's a lot of friction there. Just I like that things will probably be there for a while if its in the standard library.
Standard libraries have the same problems; in fact, part of the reason these are being removed from Python's stdlib is...they don't have maintainers.