> Its major problems aren't technical but social, and no new technology will solve those.
Really? Isn't the major problem of the current internet is inherent centralization of services because the initial promise of 100% decentralized network is simply too complex to realistically manage? I view that problem as deeply technical. Unless if by "social" you simply mean everyone should become an experienced sysadmin. (or the slight variation of, everyone should know an experienced sysadmin who's willing to run their application for them for free)
Take something as mainstream as social media. Imagine a world where Facebook/Twitter/TikTok/YouTube/Reddit/HN/etc worked (seamlessly) like bittorrent. An application on your machine when you run it, it joins a "Facebook" network where your friends see you online through their instance of the application. Your feed/wall/etc is served to them directly from your machine. All your communication with them is handled directly between the 2 (or 1000 or millions) of you. No centralized server needed. You can easily extend and apply this majority of centralized application today. The only ones I can think of where this wouldn't work would be inherently centralized services like banking for example.
There are already plenty of p2p networks that show that this is a viable solution. Bittorrent, soulseek, bitcoin, etc.
All the problems you will run into however to make this as seamless as just connecting to facebook.com are purely technical. The initial big hurdle is seamless p2p connectivity. That is without port forwarding, dynamic dns, and requiring advanced networking, security, and other sysadmin knowledge from every user. Next would be problems like what happens when the node is offline? What happens to latency and load if you need to connect to thousands, hundreds of thousands, or millions of machines just to pull a "feed"? How is caching handled? How are updates/notifications pushed? How do nodes communicate when they are wildly out of date? Where is your data stored? How do you handle discoverability, security, etc.
All deeply technical problems. Most are solvable, but you're gonna have to invest a significant amount of effort to solve them one by one to reach the same brain-dead simple experience as a centralized service. The fediverse has been trying to solve just a small subset of these problems for over a decade now, and the solutions still require a highly capable sysadmin to give users a similar (or only slightly worse) experience than twitter.com.