Unless there are some radical changes to terrestrial radio in the long term it cannot compete with unlimited data plans and calling up what songs you want to hear verbally on your phone and playing it via Bluetooth to your car stereo.
If what you say is true, there are no changes, radical or otherwise, that OTA radio can make that will turn it magically into a phone. For multiple reasons, some dealing with federal law, some dealing with physics, and some dealing with business, there is no way that a radio station can somehow become Pandora. Or vice versa. They are two things for different purposes. My studies tell me there are some 14 year old boys who listen to OTA radio. But I also know that OTA radio isn't aiming at 14 year old boys, and what I know is that boys are less likely to ever want to hear the kind of music that's played on OTA radio. So yes, I know the studies and I know that families that can afford Sirius and other subscription services likely have no interest in free OTA radio. But I also know there are millions of other people who want and enjoy what's on traditional radio. Those are the people we program to.