My initial comment was incomplete -- I wasn't clear about the use-case I had in mind. I wasn't referring to making voice calls or text messages, which are very low bandwidth and thus don't require much power from the phone battery.
I was referring to using the phone the way people use a phone today -- as an internet device, for web browsing, social media interaction, posting photos and videos, live-streaming, etc. Those activities require ~100x the bandwidth of a voice call and perhaps 10,000x the bandwidth of a text message. And they require much more power to connect reliably for those higher bandwidths.
The satellite cell services you mention are real, or under development, but check the actual bandwidth they can deliver. You'll find it's not anywhere close to what's required for today's normal phone usage patterns. Can it get there eventually? Probably, I wouldn't bet against Elon Musk.
Sorry for my not being more clear about the use-case I had in mind.
No problem. When cell phones can connect via satellite, it will be a good thing regarding people who get lost in the middle of nowhere. They will have a way to communicate with SAR, instead of having no cell service.