I'm not sure I agree that it's an unsustainable idea to keep a wrapper updated. If people really are interested in it, surely they will keep it updated. Lots of open source projects bitrot, and the general reason is lack of interest in keeping them working. Given the number of times I've seen the non-portability complaint, it's especially surprising that noone but Steve Langesek (according to your link) has seen fit to contribute code.
I do agree though that it would be better if systemd standardised those interfaces that people want to use, such as the logind interface.