FirstNet[1] is a national first responder wireless network meant to address this concern. It's predicated on the assumption that network operators have already sunk in money to maintain resiliency in the face of emergencies, thus marrying federal funds with (what is now) private sector wireless infrastructure dedicated to first responders who generally always have and use their mobile phones.

[1] https://www.firstnet.gov/news/firstnet-partners-att-build-wi...