In the end, I think Apple has gotten this right again. If you want the best quality sound, then connecting to the lightning port is going to be better because more data can be passed through it (I believe). If you want the best convenience, you should be using wireless headphones. But in no event should you be using the jack except because of legacy headphones. And basically the consumer hasn't figured this out because that jack that they know was always there.
Allow me to unpack this...
"In the end, I think Apple has gotten this right again. If you want the best quality sound, then connecting to the lightning port is going to be better because more data can be passed through it (I believe)."
Well, yes. You're saying more data will pass through the data cable than the analog cable. No argument there; it's just a matter of when the same exact amount of data becomes an audio signal, and that can happen internally or externally. Without getting into the technology of it, I can offer you the iPhone 6S. It already offers both options.
"If you want the best convenience, you should be using wireless headphones."
Personal preference. I prefer better audio quality and not having to charge/power mine; to me that is more convenient. However, wireless headphones have nothing to do with the Lightning connector or the 3.5 jack.
"But in no event should you be using the jack except because of legacy headphones."
That's not true. Without the technical mumbo jumbo, there is no way that the analog port is severely outperformed. In fact the performance will be based on the A/B test... specifically, I'm saying that if you took a DAC Dongle today, and then tested it in a 6S lightning, and the 6S 3.5, is there a difference? Could someone even tell the difference? I have my doubts, but it's possible that depending on the quality of the DAC used and the amperage it pushes, you can get a better signal.
I would return to the idea that the 6S DAC set with the internal plug is absolutely excellent, and my most standards a very well received signal chain *for a phone*. If you're doing some sort of critical listening, I'd have many questions for you.
"And basically the consumer hasn't figured this out because that jack that they know was always there."
You're right. Most consumers aren't in the $200+ category of cans. If you walk into a store now, you won't see $10 Lightning earbuds. You also won't see $10 wireless headphones. People are, I believe, fairly aware of wireless headphones at this point. So whatever figuring out they're doing, which I assume is the awareness of Lightning headphones maybe, is more of a lack of availability at a price point.
What Lightning can do, which is very cool, is sort of force the headphone amp on a customer by hiding it in the product. They eliminate what would otherwise be those clunky headphone amps that are twice the size of your phone. I think it's great that these are starting to permeate the high end of the market. I find them to be less useful unless they have an adapter, but that's my use case. Others may be interested without it. No problem.
The argument isn't that Lightning is awesome. It is. The 6S offers it. It offers Bluetooth as well. These are great features. But as I just mentioned, those in-ears and lightning cans are higher end. They're not the ones you want to take on the subway or sweat into at the gym. They aren't the ones you take grocery shopping or walking in a park. They aren't the ones you have to worry about charging ahead of time (BT), they just work immediately and without fail. And for all of those conveniences, why remove it?
When you say "Apple got it right" - I assume you mean that having lightning and bluetooth are cool. However, if you're saying that the design omission of the 3.5 is what Apple got right, the question to you is, what is right about it? All you've done is inconvenience a lot of people... and a vast majority will begrudgingly buy an adapter so their stuff works at no real consumer benefit.