Wow cool!
I doubt FidoNet will return, and it shouldn't. We could do so much more with so much less now. All of FidoNet would fit on an Arduino. FidoNet was a layer on top of dialup POTS, it had no other connection layer. It was connection based, not packet based.
I am shocked and honestly dismayed how scarce direct phone to phone communication tools are.
BT and/or wifi for neighbor discovery, clustered chaotic routing, store and forward of encrypted bundles, totally doable. THAT would work without poles or towers.
And it would be a great medium for social games and events.
Not my world though.