Seems previously one of the goals for the Flatpak project was to develop a universal app packaging format for Linux OS family that suits even exotic ones like Alpine and Void (and it did fantastic job at that).
Now the direction changed with the new team/leadership towards integration, security and control instead of "it works everywhere".
Hopefully basic features will still work without systemd-appd, otherwise we would be back to "Linux desktop has no universal packaging format" considering that:
* Most appimages often rely on specific libc of the base system;
* Snap does not fully work outside of Ubuntu ecosystem.
Now the direction changed with the new team/leadership towards integration, security and control instead of "it works everywhere".
Hopefully basic features will still work without systemd-appd, otherwise we would be back to "Linux desktop has no universal packaging format" considering that:
* Most appimages often rely on specific libc of the base system;
* Snap does not fully work outside of Ubuntu ecosystem.