But you are not using P2P to exchange pictures or video with your friend or family. You store them in a big central server that somehow magically get paid for.
Wikipedia still begs yearly for hosting whereas if people voluntered their bandwidth and space there would be no problem hosting it.
I remember eDonkey fondly. The variety of things you can get with torrents pale in comparison of what was open to us: people would just share "their" files with a huge variety of different content. Nowadays you only get a few thousands of the most popular US movies.
Hosting costs are not the main reason for the yearly fundraisers on Wikipedia. From July 2016 to June 2017 the Wikimedia Foundation raised $87.5 million in donations and spent $2.2 million in hosting.
Cost of maintaining my pictures and videos is tiny, as is cost of maintaining Wikipedia (relative to its users). Simple VPS for $1/month is enough for me, and with economies of scale, I'm sure that it's few cents per user at most. Wikipedia has no problem getting enough donation to continue its work.
I like the idea of P2P social network, but honestly I think that there's no problem to solve in the first place. While distribution of huge video files and music files is a problem and torrents solve it, that's why they are popular. It's not easy to host terabytes of video with thousands of downloads. But it's trivially solved with torrents.
