It's funny to see the development of opinion here as this story gains more and more traction. So many people have already become convinced that removing the headphone jack is going to be to their benefit when nothing could be further from the truth. Great. They save a tiny bit of space internally. Yet this is the same site where opinion is overwhelmingly in favor of making the phone thicker in order to improve battery life. Waterproof? Really? I'm on my 7th iPhone personally, we've had at least 15 in the immediate family, and I'm extremely active, outdoors a couple of hours in all weather almost every day of the year. I think I can count on one or two fingers the number of times I've had to take any precautions about water getting in the phone. It's a non-issue and there are already waterproof phones that retain the headphone jack.
Bluetooth headphones suck. You have to charge them, frequently. They sound worse. You have to deal with pairing issues and interference. We have several pairs we've tried for my wife who wants them for running. They all have issues. She uses her wired ones now.
Despite the thousands of posts written here on this topic there still has not been a single reason given as to why removing this port is good for the end user. Not a single one. This isn't at all the same as in the past when Apple removed legacy parts that were on the verge of being replaced and they just hastened their demise. There is no replacement needed for the 3.5mm jack until you can hardwire us direct to the brain. Otherwise give me one of the most robust, reliable plugs ever created without the need for an adapter that adds cost, complexity, bulk, and likely reduces quality.