"What about my legacy media/peripherals?"
On top of this, the author had to remove the "barometric vent". I don't find a lot of use in having an altimeter or barometer in my smartphone, but I do know that some apps take advantage of it (Dark Sky). Apple probably wants it to push some activity tracking feature, like the number of steps you've taken.
Apple itself would have had a lot more latitude in design since they specify the layout, and because of that, I think it is also fair to say that the article still provides strong evidence that if Apple were doing it, they probably could have included a headphone jack without compromises.
That being said, the iPhone 6/6s are the same size as the 7 from what I can see. The only obvious changes are waterproofing, headphone jack, taptic engine, and lack of physical home button.
1) Lightning is a great connector for audio.
2) The headphone jack takes a lot of space and they want to use that space for other stuff.
3) Apple has a "vision of how audio should work" on phones and they want to "get there as soon as possible." That was a lead-in to talking about Airpods
Note that they underscored that #3 was the "most important" reason they made the move.
#2 always made sense to me and I gave Apple a bit of a pass on removing the jack for that reason, but this thread's article shows that it was bogus, at least for the iphone 7.
That leaves #1 and #3, both of which involve Apple taking a a bigger cut of headphone sales. While #1 is true, it's not where the rest of the audio market is. And #3 (remember their "most important" reason) basically can be translated to "We want to sell you Airpods."
So it seems it really could have been all about Apple making more money, not about their users. Possible exception being long-term benefits created by moving the market in a particular direction.
(disclaimer: Android user, who prefers using bluetooth headphones anyway, but at least that means I don't have a horse in this particular race... :) )