That's a pipedream. Our current intermediary run cellular networks pretty much replaced all our previous infrastructure in that space because there are far fewer compromises to end user experience. Secondly, your phone doesn't have any long range antennas in it.
Do some research on VHF/UHF amateur radio. That'll give you a primer on why this is hard. Think line of sight, repeaters, traffic management.
Our current infra, even if it is paid, is cheap and miraculous.
Edit: I had a ham license once (probably still do), built VHF transceiver, only had asshats to talk to on it (locality related not technical).