OP was almost certainly saying "don’t exist anymore" to indicate that you can't rely on them to be at every corner gas station (or similar) anymore, thus making them obsolete for such a purpose as checking in with relatives. Their obscurity means you'll be unlikely to find them unless you're close enough to something like a full-service truck stop, which I've observed tend to still have payphones.
Some countries actually support pay phones. They're amazingly useful during disasters when mobile networks may not be functioning.
Example: Japan, but they're contemplating reduction. "city areas are required to have a public pay phone installed every 500 square meters, with non-city areas every kilometer. " https://japantoday.com/category/features/lifestyle/the-end-o...
If your local region doesn't have a lot of pay phones perhaps it is time to consult the local government. Change can start at the bottom.