Cell phones are laughable single points of failure. Everyone brought this upon themselves from decades of bad engineering choices, if you consider resilience an objective. Once upon a time there was a terrestrial network of small autonomous telephone exchanges. Your phone numbers were tied to geographical locations. It seemed 'inconvenient'. Now you or your signal often have to travel hundreds of miles (as the crow f…
Mesh networking standards exist that can take good advantage of cell phone hardware. Several of the phone handset operating systems are already theoretically capable of supporting it (if they weren't so locked down).
At the very least, in emergencies, cell phones should be able to network point-to-point between each other.
The barriers to doing that currently today are more political and economic than technical. It would be great to try to tear those barriers down.