A lot of the iPhone design decisions have generally had the nature of something I didn't like that some market research must have shown to be in demand. And so the iPhones have kept getting bigger, even though I've held on to my 4, 5S, and SE's for dear life.
People seem to want them, so Apple end up selling them. We're probably in the minority, and I can't fault Apple for not turning down the money.
Although I do wonder how the hell cases and screen protectors work for foldables.