You're bang on there, I have a Garmin Inreach and the subscription can be as low as $25 per month, when its not needed you just suspend the subscription. It has GPS navigation/SOS button that triggers search/you can txt from it and communicate the status of your situation with rescuers/TXT family to alert them/plots your location on a map so anyone you give the link to can see where you are. In my opinion, it's in some ways better than a sat phone.
Personally I wouldn't wast my money on an EPIRB, I had over 30 years in the Marine Safety Equipment game and once they were invaluable. The problem with them is they trigger a search and use resources that may not be needed. EPIRB's are designed to be used in water, they rely on the water surface to bounce the signal, this can also be achieved by positioning on the roof or bonnet of a car. PLB's are designed in the same manner but can't be called an EPIRB as a EPIRB must be able to transmit for 48 hours, or that's what it used to be as I've been out of the industry for some time now. Not to mention that you used to have to register them with AMSA, renew the registry, notify AMSA if you sold it/disposed of it. Just my opinion but I think they are a piece of antiquated equipment as far as land based use, they still have their place in the offshore yachting fraternity as a cheap insurance policy.
At least with the Inreach plotting capability if you were to be rendered unconscious it would be possible to see that you hadn't move over a period of time and hopefully that would alert a friend or family member to your situation.
Again, just my opinion.