I wonder what Apple take away from that summary of iPhone thicknesses at the top of the article and the author’s observation, that I agree with, that “it is a common belief that iPhones have become thinner and thinner over the years, when Apple could be keeping them the same size and including larger and longer-lasting batteries”.
What I take from it is that, apart obviously from a few exceptions, the majority of users haven’t really noticed the increases in thickness across the generations of iPhones and hence any re-establishing of any drive on Apple’s part to go thinner again would yield no tangible market benefit whereas, based on many of the comments here, using any internal volume freed up to increase battery capacity would address something that many, many users care about and that any decent review always digs down into and tries to test in some detail as soon as any new phone is released.