I have lost hope that public torrents can serve as a good availability system. The issues are not technical but "societal", ie what rules do we collectively follow, to make content available. Private trackers are perfect for this specifically because they have a way to nudge people into re-sharing poorly seeded torrents. Bittorrent helps do that, but any technology can.
> being an only seeder and getting it downloaded maybe five times
I haven't seen/conducted a thorough study, but I believe that a ratio of 5 helps content be alive for a longer duration, even if imperfect, taking into account 1 or 2 or those 5 that will disconnect and stop sharing. Everyone should target this ratio. That's why I'm ok seeding for hours as long as I hit that number, but for more obscure content I might be seeding it forever
> Which reminds me that the cost is not really nil
True, nothing is really ever nil. What I meant to say is that the cost of distribution is nothing compared to the cost of production.