Those a wireless networks. But are they "mesh", other than the name? Can I see a map of the topology? Melbourne had one like that once: https://www.melbournewireless.org.au/ It mostly worked by one guy installing an antenna on thebl roof of a skyscraper and everyone pointing theirs at that. 🤣
Nothing mythical about mesh networks.
https://en.wikipedia.org/wiki/Guifi.net
to name a few.
And there's nothing mythical about the other two things you mentoined either, just look around the protocol you're using right now. Existence proofs abound.
Discussion
they have 2370 nodes (and yes, a few "supernodes" like you're describing). the topology is good. it is absolutely a mesh in more than name.
When hurricaine Sandy hit new york, some neighborhoods were completely cut off and only had their mesh peers - which was able to provide important local connectivity to those people.
This looks somewhat promising. The supernodes are worrying ofc. Real mesh networks usually exhibit more of a small-world topology. https://en.m.wikipedia.org/wiki/Small-world_network