I switched to T-Mobile at the last upgrade interval because of this. My family looks forward to no longer relying on Garmin InReach devices when out hiking.
I think it depends on the application you're using it for.
If you're constantly using the gps - yeah, I'd definitely agree with you.
But if you're using it purely for emergency communication, you can just turn off the cell phone, and it should be fine.
It's also possible to pursue a hybrid approach by bringing a battery to change the phone.
Or, as I have done on multi-day trips, a solar panel and a battery.
Cell phones are far more sensitive to temperature issues than dedicated devices.
And when you do have an issue no external battery is going to help you because they are also sensitive.
And now, other people have some access (if non-optimal) to rescue services, despite the fact that they didn't (or couldn't afford to) pay more for inReach.
I see this as an unqualified win.
At least my work S24 says ~16 days in airplane mode + power saver. Not tested.
Works surprisingly well. You have to be outside and hold iPhone in the specifics position pointed at satellite, it tells you where to turn iPhone to to get signal.
(I’m referring to the "Messages via Satellite" feature that launched two months ago in iOS 18. This is different from the "Emergency SOS via Satellite" feature that has been around since 2022.)