No, they are not. You might think they are, and maybe they truly are to you. But ideal phone size isn't a factual discussion; it's a matter of opinion and preference. You are not right. I am not wrong. End. Of. Story.
Now which is more marketable and profitable? That's based on the majority preference. There is indeed a right and wrong answer to that question. And I think Android devices have proven that the majority wants ever-bigger phones. I don't deny this reality, and I think Apple is smart to get on that bandwagon.
But, and this is my point, if Apple is going to cater to the niche/minority customer that prefers the smaller size (and that's a big if), why not truly serve their desires and keep the small size they have and like? They should first and foremost make a giant phone for the masses, but why even bother with a second model for that minority if it's going to be bigger, counter to the entire point of a smaller model?
I'm done complaining about Apple making a giant iPhone. They are a business, and that's what makes sense, even if it's a product that doesn't excite me personally (totally acceptable). What doesn't make sense is an additional smaller model, targeted at the people who share my preference, yet still doesn't excite me/us. Who is the less big model aimed at?