A few weeks ago the annual rumor of Apple removing 3.5 mm headphone jacks from the next version of the iPhone started up again. It's probably not a question of if that'll happen, but more a matter of when. And certainly Apple isn't the only electronics company to look at getting rid of that legacy connector. Maybe it'll lead the way. Maybe it'll follow and do things a little differently and a lot better.
And it's an interesting conversation on the Android side of things as well. It's certainly possible from a technological standpoint — hell, we saw HTC try it with with an ExtUSB port in the Windows Mobile-era Touch Diamond. That's a world away, though. We're now in early days of USB-C, which opens up additional possibilities.
I could speculate all I want, but I don't make phones for a living. So I asked some folks who do about this sort of transition.