For the record it is not correct that NixOS's choice to store language packages in its own repos is unique: Slackware does this and IIRC Ubuntu and Debian both

For the record it is not correct that NixOS's choice to store language packages in its own repos is unique: Slackware does this and IIRC Ubuntu and Debian both do this. In fact, this is so common that I occasionally see warnings on package websites telling you not to install it from your distro's repos specifically because it will be out of date.