I tried to migrate friends and family to Signal a couple of years back. Only managed with 3 people :/.
Unfortunately here (Italy), WhatsApp is too much widespread as reach out method now. Especially for businesses, from restaurants to, say, the family doctor.
The majority of other distros value package managers that allow for complex graph evaluation of dependencies, and the ability to roll back. This is granted with rpm and Deb, but not for pkgsource, which is a pretty lightweight format compared to those.
As for AUR, the major distros (Ubuntu, Debian, Fedora) support 3p repositories as well. The main concern is security. IIRC one of major complaints for AUR in the past was that it didn't foresee a strongly secure distribution system.