good in basic theory. but in practice, some have alrady tried this. here are some issues found
some people thought about sing bluetooth to connect to people locally. the issue is that with mobile phones. people walk around. meaning it will keep dropping every time people using the network move more then 100 metres apart.
another proposal was people setting up their own cell antennas. this issue is with the eventual solo-owners(thousands of people independent).. would start to become a pool. where only a few people own many masts.. much like the mobile network today