Matrix is terrific. I've "converted" some friends from Signal to Riot and we're not going back. Video/calls and group chats work a lot better, and the riot.im web client is excellent (at least, compared to Signals lack of).
I've also stopped using an IRC client and just use a Matrix bridge. Really happy so far.
Main drawback is that E2E is a bit clunky to set up, and downright confusing for non-technical users.
Not quite the same, but the time zone database was voluntarily maintained by some random guy for decades, until he got a lawsuit in 2011 and ICANN eventually took over.
The problem with systemd usurping basic Linux functionality is that it makes it really difficult for non-systemd distros to keep up.
It's not like you can run 'systemd-udevd' standalone, for example. Instead there are massive "porting" efforts like eudev and elogind, just to extract the functionality BACK from systemd. And then you have obsolete-but-necessary components such as ConsoleKit and PolicyKit that are stuck on ancient pre-systemd versions with no current replacement.
I started using systemd back before they even took over "udev". Back then systemd was a breath of fresh air. Now I'm using a different service manager and observing systemd gobbling up various critical parts of the Linux desktop like some damn Katamari is like watching a train accident in slow motion.