It's really not perplexing. The state of the art communication systems are designed to permit communication if the crew wants to communicate. In the case of flight-370, whoever was flying the 777 did not wish to avail themselves of the plane's communication systems.
That's probably something that will change in these times of terror. If the operator wants to fly commercial service or fly into an airport, the plane must be hardwired to communicate whether like it or not. There'll be some kind of system in front or running in the background. No choice will be given about it.