BitTorrent would likely increase latency, not lower it. The bit torrent protocol is very inefficient for small files and large numbers of files (https://wiki.debian.org/DebTorrent - see "Problems").

But I think your question is more "why not use p2p to download files" for which I think the answer is likely "because they don't need to." It would add complication and overhead to maintain. An FTP/HTTP server is pretty simple to setup / maintain and the tools already exist to maintain them. You can use round-robin DNS to gain some redundancy and a bit of load spread without much effort either.

What are you talking about? All that torrent traffic that my ISP sees is definitely Linux ISOs.

Just doing my part

I suspect if this was enabled by default there would be uproar from people annoyed the distro was stealing their bandwidth, and if it were opt-in then very few people would do it.

Windows Update uses peer to peer to distribute updates. It's one of the first things I always disabled.

Most common/relevant/larger distros do that at least for the install/live ISO.

One reason is privacy and hence security. If you share a package, you also share the information that your system contains the oudtated package "xy" which has a backdoor and can be accessed by a hacker.

I'm not sure if that is a valid argument with atomic image distros since you share the whole image. And the tracker could just disable the old image as soon as the new image arrives.

Because HTTP is simpler, faster, easier, more reliable.

The motivation for a a lot of p2p is to make it harder to shut down, but there is no danger of that for Linux distros. The other would be to save money, but Debian/Arch/etc. get more than enough bandwidth/server donations, so they're not paying for that anyway.

https://wiki.debian.org/DebTorrent

https://wiki.debian.org/DebTorrent/SolutionIdeas

That's actually a really interesting idea. Windows even does something, or at a point did something, similar with system updates.

Peer to peer packages would have some privacy, and potential security issues of course but I like the thought

There is an apt variant that can do this, but nobody uses it. BitTorrent isn't great for lots of small files overhead wise.

IPFS is better for this than torrents. The question is always "how much should the client seed before they stop seeding and how longs should they attempt to seed before they give up". I agree something like this should exist, I have no problem quickly re-donating any bandwidth I use.

Nix has an open issue on integrating IPFS support.

There's also an old tutorial.

Metallica ruined it. They made it seem as though torrenting was evil because their content was being downloaded. Poor babies.

Over time I've seen several groups tinker with p2p protocols for packages. Latest using gnunet/ipfs for Guix packages. But I've never seen a working/integrated system. Weird..

Some distros do this already.

Alternative downloads

There are several other ways to get Ubuntu including torrents, which can potentially mean a quicker download, our network installer for older systems and special configurations and links to our regional mirrors for our older (and newer) releases.

BitTorrent is a peer-to-peer download network that sometimes enables higher download speeds and more reliable downloads of large files. You need a BitTorrent client on your computer to enable this download method.

https://ubuntu.com/download/alternative-downloads

Another thing not mentioned yet is maintenance overhead. These distros operate around the clock, all over the world, with talent from the likes of RH and co. There are far fewer people (who run your mirrors) who know how to maintain a torrent tracker (or similar), and on top of that, I haven’t really seen any good BitTorrent caching methods. Support would need to be added to your package manager of choice.

It also comes down to most client having asymmetric bandwidth, and that most users do not have every package installed and therefore can only distribute a very small amount of the total distro. Those users probably don’t want to be constantly uploading, either. I also can’t imagine torrents are too fun to work with when it comes to distributing constantly changing package manager metadata, too.

Reminds me of the Talk about distributing firmware.

Bittorrent is poorly pretty suspicious which may be used as an argument. But I dont see the reason really.

FWIW the "opposite", namely Webseed, exists http://bittorrent.org/beps/bep_0019.html so... maybe some already do but it's not even noticed because Wedseed of mirrors handle the load?

That what Debian does with ISOs. However, no one uses it.

If anything IPFS might be good for packages as the IPFS program could he embedded into the package manager.

To add to everything else mentioned, many places (schools, workplaces) don't allow any usage of BitTorrent, even legal. A guy at my uni got yelled at for torrenting a Linux iso. Not to mention depending on where you live your ISP might be interested in that activity unless you're using a vpn.

At least Kali and Arch do