I think looking at the two major enterprise players (Red Hat and Canonical) can give hints.
Fedora: run by Red Hat, upstream of RHEL. No way they are going to allow an unreviewed repository to be shipped with fedora by default. But they do have guides to add RPM fusion, and copr repos (the closest equivalent)
Ubuntu: run by Canonical. No way they are going to allow an unreviewed repository to be shipped with Ubuntu by default. But they do host and have guides for PPAs (closest AUR equivalent)
Debian: kind of the base layer for a lot of other distros. Debian itself is kept very minimal, and has a whole philosophy on what packages are allowed.
Edit: I realized this implies PPAs, copr and the AUR are the same when I know they aren’t functionally. I am just trying to highlight the motivations behind the distros and how it may play a part
PPAs aren’t convenient at all compared to the AUR. Pacstall is the AUR for Ubuntu it just needs more packages. I would still be on Linux Mint if Pacstall was as extensive as the AUR.
I think looking at the two major enterprise players (Red Hat and Canonical) can give hints.
Fedora: run by Red Hat, upstream of RHEL. No way they are going to allow an unreviewed repository to be shipped with fedora by default. But they do have guides to add RPM fusion, and copr repos (the closest equivalent)
Ubuntu: run by Canonical. No way they are going to allow an unreviewed repository to be shipped with Ubuntu by default. But they do host and have guides for PPAs (closest AUR equivalent)
Debian: kind of the base layer for a lot of other distros. Debian itself is kept very minimal, and has a whole philosophy on what packages are allowed.
Edit: I realized this implies PPAs, copr and the AUR are the same when I know they aren’t functionally. I am just trying to highlight the motivations behind the distros and how it may play a part
PPAs aren’t convenient at all compared to the AUR. Pacstall is the AUR for Ubuntu it just needs more packages. I would still be on Linux Mint if Pacstall was as extensive as the AUR.