No, it isn’t because they removed the headphone jack.
Actually, its because they’ve made it waterproof. I’ve owned almost every iPhone since they arrived, except iPhone 5, 5S and 6S and every one I’ve owned has only last 18 months or so before I notice a severe degradation of battery life.
Most recently my iPhone 6 Plus was no longer lasting a full day after about 18 months of use. A quick repair job with a battery and kit from iFixit and my iPhone 6 Plus was as good as new, lasting a day to a day and a half.
This doesn’t look possible on the iPhone 7 due to seals and adhesives used to make the phone splash/waterproof. I’ll stand corrected when iFixit tear down an iPhone 7 in the next few days. However, I’m going to make a bet that its not user fixable, at least not whilst retaining the waterproofing.
What are your thoughts on iPhone 7? Will you be getting one?