I'm betting it's a disconnect from the tech and engineers and the PR people at Apple you see quoted in these articles. The $9 Apple lightning to 3.5mm dongle should be capable of up to 24bit/192kHz audio.
The iPhone 7 arrived without the jack input, but it does come with an adaptor cord featuring a Lightning connector and a 3.5mm jack entry. You can also buy the adaptor as an accessory to use with any Apple smartphone or iPad.
www.qobuz.com
It'd be quite odd that they would force you to use a 3rd party DAC/amp when their own $9 version should suffice.
As for wireless, if the internal hardware could physically support it, I'm betting on a firmware update for existing W1/H1 headphones to have ALAC via the ultra wideband chip. For CD quality lossless ALAC, you're looking at less than 1Mbps, and UWB should be capable of hundreds of megabits.
Apple has added its U1 chip to even more products, and is clearly planning to make Ultra Wideband a major feature of its device ecosystem? Here's a breakdown of UWB, what it does now, and what it can do for you.
appleinsider.com