While messaging with iMessage, Facebook messenger, WhatsApp, etc. can be done over WiFi only, calling is traditionally reliant on a cellular provider. The new iPhone only requires a WiFi network, and with the proliferation of WiFi and the first city-wide networks (e.g. Barcelona), it is possible that in the next decade all communication will be done over the Internet.

Also, during a recent trip to Japan I saw an $120 SIM card that gives unlimited Internet access for a year. This works out to $10/month, which is far less than what I pay for Verizon. So in a way this new iPhone may eventually cause cellular networks to primarily become providers of remote Internet access, as telephony shifts to the apps that the local people use to connect with each other.