so if phones have the capability to make emergency calls regardless of the absence of a carrier's signal then why can't phones make calls to other people this way too? If you say its just a network level priority, what would happen if other calls were given this priority too? Can our current system not handle that kind of volume?

also now Im interested in buying a satellite phone...considering that sailors on the ocean and mountaineers are using it in super remote regions, that means satellite signals must reach everywhere, right? Like you should be able to access a satellite connection from anywhere on this planet. Is there anywhere where a satellite signals can't reach even if you have the appropriate devices?