Rustup downloads toolchains from third-party (to the distro) repositories; distros do not want to be in a position where they can no longer build packages because of an external service going down.
So, if you are developing something you want to see packaged in distros, it needs to be buildable with the tool versions in the distro's repositories.
(Not just rustup- Debian requires repackaging Cargo dependencies so that the build can be conducted offline entirely from source packages.)
So, if you are developing something you want to see packaged in distros, it needs to be buildable with the tool versions in the distro's repositories.
(Not just rustup- Debian requires repackaging Cargo dependencies so that the build can be conducted offline entirely from source packages.)