The fact Samsung managed to get IP68 moisture resistance with the Galaxy S7 and S7 Edge phones show that Apple did not need to remove the 3.5 mm headphone jack. In fact, I wouldn’t be surprised that the pushback from consumers ends up being so strong that they can’t figure why the iPhone SE and the iPhone 6S/6S Plus models (which will continue in production at a lower rate) are outselling the iPhone 7 models.
I suspect the highly improved camera and processing of photos will drive sales - apart from plugging headphones into a different hole.