I do not believe that making phones capable of contacting satellites, even just for texting, would be technically or economically simple; if it were, it would probably be at least an optional feature on many high-end phones. For developing countries in particular (to which most of your scenarios apply), the extra cost may very well be prohibitive.
First World users could probably afford a moderate increase in cellphone prices, but in the First World it’s entirely possible to never leave regular coverage for extended time periods; and when you do, it’s likely to either be in contexts wheres you would bring a separate GPS transmitter of some sort (extended camping / climbing trips, seafaring) or because you’re somehow shielded from cell towers, in which case I don’t know if satellite phones fare much better.
I do not believe that making phones capable of contacting satellites, even just for texting, would be technically or economically simple; if it were, it would probably be at least an optional feature on many high-end phones. For developing countries in particular (to which most of your scenarios apply), the extra cost may very well be prohibitive.
First World users could probably afford a moderate increase in cellphone prices, but in the First World it’s entirely possible to never leave regular coverage for extended time periods; and when you do, it’s likely to either be in contexts wheres you would bring a separate GPS transmitter of some sort (extended camping / climbing trips, seafaring) or because you’re somehow shielded from cell towers, in which case I don’t know if satellite phones fare much better.