In 2011, I had bought a new Tundra CrewMax Platinum. It was almost fully loaded and had Toyota's navigation and bluetooth systems in it. It was the worst, least useful, most trouble-ridden system in a vehicle I had ever owned. The system in a 2006 Acura I had blew the doors off of it.
That was the point at which I stated that in-car navigation was going to go the way of the dodo, and we would be able to plug in our phones and have the small form-factor screen mirrored to a larger in-vehicle screen that could provide touch feedback back to the phone. We're just now starting to see some of that with CarPlay and Android Auto, and I believe it will continue to improve until the phone becomes the center of the in-vehicle system.
Another that your phone needs to be able to do is carry around your health records. With TouchID and similar technologies from Android coupled with Near Field Communications and Bluetooth, we should be able to -receive- data from a health care provider's in-office device and transmit data back in much the same way we can load a credit card into our phone and use it to pay for our McDonald's coffee. Taking our records with us this way, and maintaining them securely on our devices, should be the norm in the future. When you go from one doctor to the next, you have all of your records with you.
Does FaceTime bridge a gap for devices that aren't cellular phone service enabled? Not really. It does in a way, but only if the person calling me is -ALSO- using FaceTime (which immediately rules out half of the smartphone carrying public and probably 65% of the population overall). When video calling is completely the norm and uses a completely ubiquitous protocol and communication method that works on any network, then it might have a shot. Google voice has a ten-fold better chance at bridging that gap because it can forward to all kinds of phones and can also be accessed with SIP clients. So, it would operate on more operating systems, more devices, and support more kinds of inbound and outbound calls than FaceTime could fantasize about right now.