There has been speculation that Apple would build this into their phones, which IMHO would be a killer feature. Imagine having an emergency feature that could be used anywhere on earth. How much would you pay per text? $5 per text message would be an absolute bargain in many of these remote locations.
I'm not sure how... the InReach (and similar products) are a Iridium satellite communication system that requires a bit more heft in the signal (up and down).
When you look at the iridium phones ( https://www.iridium.com/product-type/satellite-phones/ ) those aren't small things (look at the antennas).
Then you've got:
> Enhanced Battery Life Up to (4) hours of talk time, (30) hours of standby
for a non-smart phone.
I'm not sure how Apple would be able to incorporate a "no cell phone tower in sight" system... without also packing on the rest of the iridium system and making a much more bulky device.
Also, while sure it would be nice if something were a no/low-cost add-on to a regular smartphone, the average consumer probably wouldn't pay much extra, much less an incremental subscription fee. And there's something to be said for a rugged, potentially safety-critical, standalone device that's separate from your phone.
On antenna - you can probably build purpose-specific satellites for text messaging that does not require big antenna. Iridium is 485miles high orbit - you can probably have satellites at closer to 150-200 miles elevation
- https://ast-science.com/spacemobile/
The former even inked a partnership with AT&T and Vodafone: https://www.lightreading.com/ossbss/vodafone-atandt-sign-up-...
It looks like they've even successfully tested it: https://techcrunch.com/2021/09/29/lynk-demos-global-satellit...
This would likely be a very high-cost option, but it does seem to be possible. The key is that these satellites are much closer to earth than Iridium, I guess.