Does not bode well for non-systemd using distros and non-Linux OSes that can currently run GNOME. :-/
On the bright side, it could possibly turn out to be good for other DEs though.
Haven’t used GNOME in a long time, but it looks to get even more integrated. It’s gonna take a lot of effort to keep up the shims around systemd that enable gnome on e.g. FreeBSD (if I understand correctly), so those may get outdated or altogether go away. Not that non-linux OSes were ever a focus for GNOME. Unless I’m misunderstanding how it all works (haven’t kept up with linux-land in a while).
“Neither will this change affect application developers for the time being as XDG autostart files continue to be supported and are prefered at least for the time being.” (emphasis mine).
This might not impact apps written for GNOME, but most probably makes whole DE (almost) impossible to run on non-systemd distro or system. Only hope we can have in this matter lands on hands of Funtoo and OpenBSD developers who so far are taking great effort in making GNOME run without it.
There are other distros like Gentoo and Void where developers also contribute to a lot of these stubs to get Gnome and other tools to work without systemd.
It’s almost as if non-systemd distributions are filling in that tiny market share that use to be all of Linux in the 90s.