I'm calling it right now...once Apple gets rid of the headphone jack in the iPhone 7, in the next year or so, hardly any smartphones will have them.
Let's hope for good wireless alternatives that don't disconnect all the time and don't sound like a carwash.
If this actually happens USB-C cables won't seem like such a big deal, compared to an industry standard that has been around since the dawn of audio devices. The adapter will probably be around, say, 30 bucks