This has already happened in LTE--everything is packet-based and any traditional "telephone" things are provided as a service (from a system call the IP Multime

This has already happened in LTE--everything is packet-based and any traditional "telephone" things are provided as a service (from a system call the IP Multimedia Subsystem) on top of that. IIRC, 3G networks were the last to make some distinction between packets and voice circuits.