[zare_st]

Why would systemd unit files matter for FreeBSD? FreeBSD has its own rc system and its own ports and packages and maintainers. If and when some major software starts lagging behind the upstream because of runtime issues, then it's time to discuss the alternatives. Right now such things do not happen.

FreeBSD had to mock several parts of systemd in order to port newer GNOMEs that are dependent on systemd. rc still runs this software, but unfortunately software depends on systemd sockets which is absurd design choice but here we are. Again mocking the absurd interprocess part is the way to go, as opposed to supporting entire specification and API of systemd.

"Any unix" doesn't cut it, too general, too broad. You did ask in dual sense in your original question but then you specifically stated FreeBSD as an example; so I'm answering for FreeBSD specifically.

The problem that I have with opinion in your post is an implication about groups of people - people with skills that should supposedly write a systemd clone for FreeBSD or other Unices, and people without skills that are supposedly waiting for the first group to do some work so they can enjoy systemd on *BSD or wherever. Let me be blunt here, I can assure you this is not the case. Systemd is not a factor for anyone in BSD world and it's a factor only for people that would like to migrate from Linux and retain their usual workflow and muscle memory.