Adapters are bad. Always.I'm likely in a minority, no change there but I really don't mind that they didn't go USB-C. In fact I'm sort of glad in one way and that's because it won't hold Apple back in future developments.
By which I mean that Lightning was released onto the market in 2012 and it took a full 2 more years before USB-C finally came to market. I'm less than bothered that Apple aren't limited in that way.
Really it's not Apple that are preventing universal compatibility either. Just as we've seen for the past couple of years there's nothing preventing manufacturers from including all 3 standards in their cans. Lightning, USB-C and good old analog, have been included on headphones from some manufacturers for a while, no reason why they can't continue to do so.
There will also be a glut of converters and adapters flooding the market before long too. It's really not that much of a big deal as some people make out. There are those that will grumble about changing cables or using adapters.
Me, well I've been doing that sort of thing for a lot longer than even our new fangled digital audio existed with the likes of 3.5mm to quarter inch headphone adapters, so I don't think it's a big deal.
It's fine your used to it, but wouldn't it be nice to never need one?