Honestly, default behavior should be to at least share package files on the local network. But sharing to the wider internet should be fairly trivial in <current year>, we have no shortage of technologies that accomplish this.

I wish more systems had this kind of feature. I have a fat fiber connection, I'd be thrilled to pop up an unofficial mirror for something like a Linux distro. I've tried mirroring Linux ISO torrents, but it seems almost nobody ever downloads from a torrent, so I end up never actually uploading any of these images.