I touched upon this a couple of weeks ago. I have given it a few more thoughts and concluded that the "proof of concept" theory must be right and all the core apps like Phone, Messages, People, Gallery... are nothing more than a tick in the box. They have to include them to be able to sell the device as a phone at all, but they did not bother giving them a grain of attention more than what was the absolute minimum to be able to say they are there. Presumably because they consider those things secondary, to be ultimately implemented by the licensing partners they are hoping to get. Licensing partners whose primary expertise is mobile communication.