The hard thing is that most successful disruptions come from startups who are ignored by incumbents. In data they're motivated to keep even the lowest profit clients, so startups face their wrath from the beginning. It isn't pretty.

Mesh networks. But I think those don't have a business model.

And it's very low throughput/high latency.

I actually don't think so. If it is just for contacting people in your neighborhood, then it works fine. If it is for people in the same city, then the city could organize something as a utility. Mesh doesn't have to mean 'on every users' device' or even p2p.