I never understood why they don’t support the subsonic protocol.
Also, there’s no native Jellyfin app for my phone.
In the end I changed to Navidrome and use it with a subsonic-compatible app.

Also, my server is still PHP-free and I’d like to keep it that way.

So to answer your question: OpenSubsonic is only for music, and Jellyfin does much more than music. Adopting OpenSubsonic would mean maintaining two APIs, which doesn’t make a lot of sense.

Meanwhile Navidrome is adding Jellyfin API compatibility to get access to more clients :P

TL; DR all the oldest members who’ve already not really been contributing because they’ve moved on in their lives have officially handed the reins to the people actually doing the work.

We should celebrate these kinds of changes. Like its great that they’ve already achieved so much and not just that, but left behind a group of folks just as committed in the future of the project.

I always feel that posterity of your work beyond your own contribution is the real achievement and a sign of humility.