I was referring to the customer backlash aspect of it. Too many people rely on the 3.5mm jack in their phones.
Oh I know what you meant. But that particular adapter did one thing only, it took the same signal, and allowed headphones with plugs too big for the iPhone hole to be used. And I think Apple charged something like $10+ for theirs. It was a completely pointless thing to do, and although there was seemingly a rational explanation for it (Apple was concerned that larger headphones would put too much strain on the connector), the better solution was to re-engineer it so that any headphones could be used.
This is something completely different. Apple is likely introducing new HQ audio capability along with iTunes support, which is one way to spin it. They're probably going to release an industry defining set of bluetooth headphones and earbuds. They're likely going to give away Lightning earbuds that are higher quality than those most people currently use. Adapters will likely enhance the quality of the audio most current users are getting (another marketing point), and Apple will make them reasonably affordable and elegantly styled to be virtually invisible. Lightning headphones will include things like noise cancellation without bulky batteries, and other digital controls not possible with the analogue jack. In other words, so many more options to using the 3.5mm headphone jack than the original iPhone situation. And Apple will have to spin this. And my guess is they will introduce some new exciting feature that they can use to justify reclaiming the space of the old jack.
So yes, there will be some backlash, but isn't there always? You say "Too many people rely on the 3.5mm jack in their phones", but I'll bet Apple has a pretty good idea just how many people that is, and in particular, how many that are using their flagship phones -- because that's all this change initially affects in the first year. And, it might only affect the base 7 customers, and not the Plus customers, thus driving upgrades (though I bet Apple will eliminate it across the lineup to drive wireless adoption). The SE and iPhone 6 will still have 3.5mm jacks for the low end customers who probably use the headphone jacks the most because they can't afford BlueTooth headphones, much less new high end headphones. But the high end Flagship customers may not be as attached to them.
And the backlash may be short lived as other phone makers start dropping the headphone jack to make room for other features too in order to stay competitive with Apple, at least at the flagship level. So Apple sort of has this covered for the people who absolutely can't afford to make the transition -- and there's yet another explanation for the cheapest iPhone Apple ever offered also being almost as functionally featured as the most expensive phone. And for everyone else, it may not be that big of a deal. Certainly not as big a deal as having to buy an adapter simply because their plug wouldn't fit.