It exists, it's named torrent. All of sci-hub content is avaliable as a magnet link for you to download and seed. If you want more recent projects, libgen content is on the IPFS
This is the kind of thing where getting a scuzzy blockchain involved would be ludicrous step backwards. Torrent isn't new tech but everyone seems to have forgotten it exists.
Incentivized onion routing networks like the Oxen network or Nym offer the potential for fast, anonymous filesharing, while decentralized storage networks like Sia or Filecoin could act as censorship resistant repositories.