I understand your points and can see that you understand the problem very well.
However, my main point is that the only real way to test a P2P solution properly is to have an official test case.
If we have multiple different P2P solutions that are all testing in a fragmented way then even when a solution shows real promise people will still say that they are not sure if it can scale properly.
I propose that the foundation sit down just for an hour together, pick the best P2P option that they believe has a chance and add a nix service nix.experimental.p2p-cache.enable then we can test that solution at scale right now. Then if it breaks, then we will know exactly why and either say once and for all that it just can’t scale or find the main cause and solve it either by switching to a different P2P solution or patching the existing once.
Otherwise, I believe we will be forever stuck in small isolated testing environments and be forever waiting for “will it scale” question to be answered.
If P2P is going to be a win, then the Foundation willl have to pick a winner at some point any way.
Based on the amount of community interest in orginal The NixOS Foundation's Call to Action: S3 Costs Require Community Support - #171 by Federico post I believe the community really wants to be able to have a chance at helping more than just giving more money or finding the cheapest hosting solution. While interest is still high in this issue it is the best time to test a P2P solution. If we wait a few years then the interest in this issue could drop resulting in less desire to work on a community run solution.
Also, the nix community is full of really smart people who can handle working through an experimental caching test.
Nix is mostly used by devs who are very invested in this ecosystem and are more than willing to work on making it last for 100 years.