Well that's your opinion. Moreover it's subjective based on use.
Some audiophile headphones come with a 1/4" adapter that fits over the 1/8" plug. There's no reason an outboard DAC has to be any more cumbersome. Moreover you're assuming quite a lot that whatever gains are merely cosmetic, as well as whether said gains are worth having an adapter.
Why would you assume that? I can imagine an inline charging plug with Lightning male on one end, Lightning female on the other with the headphone cable connecting in the middle of the plug -- and that's just what I immediately came up with off the top of my head. Moreover, in order to use headphones and charge now while my iPhone is on it's dock, i have to plug them through the dock -- which is so awkward, I never do it. So if that's important to you, you just buy an adapter that lives on the end of your Lightning charging cable that allows you to plug into it while you're charging.
Apple already does this with the HDMI connector. That may not be important to you, but for people who use this feature a lot, their problem has been solved, just as it will be for you. Or maybe you'll just switch to Android as they cling to 19th century single function technology invented for the first telephone.