There's a pro-consumer approach to this and an anti-consumer approach, as far as how Apple handles this.
The most pro-consumer approach, whether people are pissed off at the time or not, is to kill Lightning and go USB-C while simultaneously dropping 3.5mm. One and done. Cheap and small DACless adapters for your existing wired audio since USB can pass analog audio signals, and Apple helps usher in the new definitive platform-agnostic standard that benefits everyone tremendously in the long run and will unify consumer electronics ports worldwide. USB-C can do almost anything as good or better, usually much better, than any existing specialized port can. The sooner it's the One True Port the better. Lightning, on the other hand, is annoying crap you deal with because you use iOS, designed because the legacy dock connector needed ditching and micro usb was a kind-of-bad standard too, but Lightning will never be anything more than an intermediary proprietary Apple-only bandaid solution with overpriced cables. Apple isn't trying to get other consumer electronics devices to use Lightning. The writing is on the wall and Apple heavily co-designed USB-C themselves. It's the Macbook's only port. It's just a matter of time.
However, I find it very unlikely that both changes would happen on the iPhone 7. Not unless we're really lucky. 2018 with iPhone 8 at the earliest for dropping Lightning? Most people are on a two year product cycle (or more) with iOS devices and to them Lightning is still the annoying new thing they're coping with.
USB-C, you mean. Lightning isn't for non-Apple devices and can't really do anything useful at all aside from be small and plug in bidirectionally and make Apple licensing money.
USB-C, though: even just with current 3.1 specifications, can already easily replace wall outlets for almost anything other than major appliances. You could power your 80" TV with USB-C instead of your wall outlet, and also connect your receiver or content device to your TV for 4K+ video/audio with USB-C instead of HDMI, and run your gigabit internet connection from your router to your home theater with USB-C instead of CAT-6.
Do it, Apple. Do it.