I've been really impressed by plexamp since I started using it 2 years ago. Feels like they've been cracking out loads of great new features in that time, and sonic analysis is at the core of my favourite: Guest DJs. The app has really changed how I listen to my music for the better.
I understand wanting to move away from plex, especially for tv/film stuff, but plexamp really feels like a passion project by some of the devs. I'd love to hear if anyone has any alternatives, but nothing else I've looked into hits the mark.
An issue with the torrent scheme is efficiency. Networks of home computers will suck down considerably more power from (potentially) less than ideal energy sources than dedicated servers in well-planned locations (i.e. near reliable renewable energy sources, with backup generators). I don't see a way to have this without involving large institutions, whether private or public.
Regarding media creation, there's a middle ground between direct payment and government-sponsored: Universal Basic Income, or a related scheme of generic grants for art/education producers. Ensuring people don't starve or become homeless as they start projects or grow large enough to be sustained by direct payments from an audience could foster this sort of growth.