I wish PLB's were a little more flexible, so they could be used for general purpose 2 way comms (like InReach) rather than simply summoning rescue at coordinates XYZ without even indicating what kind of emergency it is. They are also quite expensive. On the other hand, if they were widespread, people would be activating them foolishly all the time.

There seems like no alternative to satellite comms in the open ocean; but on land near some semblance of civilization, I've been wondering whether low speed digital ham radio modes could be used for this purpose. A pocket sized tranceiver with a wire antenna would likely be able to send and receive text messages at very low speed (a few seconds per character) with 100+ miles range. So it would be a matter of organizing protocols and receiver networks for emergency and personal comms with these things.

The transceiver would be something like this: https://hackaday.com/2021/09/25/the-simplest-ft8-transceiver-youll-ever-build/