It makes sense to me. Developers work on a project (and most definitely open source developers) because they feel some friction with a system. Maybe it’s a task they want to automate, or a bug in some software they need to use. But either way — there must be some pain point that is causing them friction. This is what causes some program/feature to be written or updated or fixed.

If those developers have a perfectly good work around, then there is no pain point for them. It doesn’t matter if it is a pain point for their GUI-exclusive users. If they don’t feel the pain, it won’t be prioritized.[*]

This isn’t a criticism of Gnome per se, but rather a reality of time management. There is only so much time to go around, which means features and bugs get triaged. If none of the developers feel like this is enough of a pain to get into the quagmire that is the GtkFileChooser (?) widget, then it will not be touched.

[*] That is, of course unless they are being paid to do the work. If you are volunteering, then you get to choose what work to do. If you’re getting paid, the suddenly not working on the file chooser could become a pain point for the developer (as they might not get paid). Which is the major advantage commercial OSes have over their open source competition.