The Four Most Expensive Words in the English Language: "This time is different"
Anyway, on to the actual topic... I need to sit down to give this more thought, but I still think there's value in P2P networks, and it's worth pursuing. You should be able to easily replicate and share content that you care about. The big incentive is being able to keep your own copy and being able to do whatever you want with it. How many times have you tried searching for an old YouTube video, only to find it got taken down?
Another example: package managers! You want to have a machine-local cache, a remote cache for reproducible builds and deployments, and whatever other remotes you get the original packages from. Maybe different registries have varying content policies, and you can pick your favorites. If you have a few developers in an office it's a lot faster to grab dependencies from the laptop of the person sitting next to you than a CDN.