I can see people paying an extreme rate of say 10$/minute with serious warnings in a true emergency. But worldwide it might only be 100 phones at a time even with 10’s of millions of iPhones. Meanwhile averaging 100 calls * 10$/ minute is 1/2 billion dollars a year which could pay for bandwidth on LEO satellites.

Those numbers are of course pulled from thin air, but iridium suffers because few are going to keep such expensive service on a just in case basis. However, the technology and economics are really close to working out.