> modern iphone will have zero problems being accidentally dropped in the deep end of a pool, or in a lake.

So which benefit can you make up to explain why older iphone models with low water resistance also didn't have replaceable batteries?

Also it's not really true for the modern phones either since there are rare models with high ip68 water resistance and user replaceable batteries

So it's not that I ignore the benefit, I deny its explanatory power and doubt its size