Meshes are powerful. They're great at the community level, but scale is an issue.
With the low price of very large thumb drives these days, sneakernet would work.
It would be interesting to see something DHT like IPFS overhauled to work on intermittent mesh networks.
Maybe something in between IPFS and SoulSeek. You keep a list of what you want, when someone comes on line with it you get it, or perhaps we all set aside a couple hundred gigs to fulfill requests.