I've played around with a few different "simple" mesh techs in my time, some of the really cheap/easily available stuff can be really useful. I've seen examples of people sending entire kilobytes-per-second of data over a kilometer with the right antennas and line-of-sight with cheap, sub-£100 kit.
Things like LoRa which I've not had a chance to play with yet look extremely promising too for long range, low bandwidth.
If there was good reason for it, and sufficiently easy to set-up kit, I don't see why more people wouldn't help build out networks by setting up routing nodes in their homes; everyone installs a WiFi router because their ISP tells them to, but what about if people's only choice to get internet was to add a femtocell or similar (and it was legal and cost effective)? People would do it.
The real hold up, I'd say, is not so much effectiveness, but need. Nobody _needs_ to usurp the role of their carrier and build out a community network, so it doesn't happen.
If for example, using that network became so costly, say for example, like electricity recently has in the UK and Europe, that for many, building out their own infrastructure with solar and batteries became cost effective, I could see it happening here too; with frequency band licensing etc likely being the main barrier.
