Water resistant? Those ratings are lies anyways, and nobody is going to bring their expensive smartphone on a diving trip to take pictures - or even take it surfing without a waterproof case. In practice "water resistant" means "won't die from an occasional splash", and that can be achieved perfectly fine by repairable phones.
Now, I don't know about surfing, but I regularly strap my iphone to my motorbike's handlebars to use as a GPS. No case. I don't particularly enjoy doing this under pouring rain, but it does happen, and the phone gets drenched. However, to the point about people wanting this, yes, I do. I would also love a replaceable battery. My old Galaxy S5 had both features, so saying that waterproofing means non-user-replaceable battery is a lie.