Here in Northern California, people are finally realizing that POTS is fairly good thing to have in an emergency, just as AT&T is petitioning to remove the capability forever.
After the Napa Earthquake (ten years ago in August), PG&E power went out, so the cell towers switched to battery backup. Some towers lasted all of a couple hours, some failed immediately (most batteries hate being kept at a high charge level). PG&E was out for a couple weeks to some areas ... so many people were without telephones for the duration of the emergency.
And people laugh at me because I insist on keeping POTS capability. I'm not a neo-luddite, I'm an aging techie who knows how things work.