Not people arguing that there will be adapters so this change doesn't matter. I couldn't think of another thing more guaranteed to break than an adapter sticking out the bottom of my phone, and even if I don't break it it's definitely gonna vanish within a week.
Technology is meant to be evolving to make everything easier, not making it more difficult so you need to buy adapters to use on your phone for earphones that work on every single other piece of technology in the world. Isolating your product from the rest of the market is an awful move, especially if it's gonna drive the price of your product up through the roof with requiring people to buy fancy specialist headphones.
I have confidence that Apple are not stupid enough to even properly consider this idea, but if they do implement it I'll be jumping ship straight away. They can **** right off with their making life more difficult bullcrap.
-> The Lightening Adapter was completely different as people are used to phones having different chargers. People will be less likely to accept different chargers and special earphones, at that point it's just going too far.