It was only a matter of time when the 3.5mm jack was discontinued. And since Apple is including an adapter I don't see the big deal here.
I agree that the adapter
should be included but, come on, if it is, I'd be forced to ask "who are you and what have you done to the real Apple?" - odds are it will be an extra $10.
Having co carry an adapter around on the go isn't the terrible privation that some people make out, but its hardly an upgrade, and it's not clear what you're getting in return. iPad Pro-quality speakers might be nice but, lets be honest, those are only "high quality"
relative to what you would expect from such tiny speakers, so they're not going to replace decent external speakers.
Also, as well as investing money in high-quality headphones, people plug phones into home HiFis, cars etc. and often
charge them at the same time. So it will be interesting to see if the adapter includes a lightning socket for charging (which will also make it more bulky on-the-go). Or there's the Lightning dock (more $ and not suitable for in-the-car).
Even my Bluetooth headphones have the nice feature that - if they run out of juice or you encounter a Jobsworth flight attendant in the air* - you can plug them in via a 3.5mm cable.
(*the idea that turning on WiFi would cause the plane to fall out of the air seems to have been abandoned now that the airlines have realised they can charge you money for internet access - but the rules seem a bit ambiguous on Bluetooth).