Either: 1) Apple thinks it won't be so niche in the future. 2) It's niche but profitable because those buyers who exist will pay a lot. 3) Apple made a foldable iPhone because they don't know what they're doing or they hate money or something.

Similarly, Apple doesn't make a small phone because either: 1) It's too niche to be profitable. 2) It could be profitable but those resources are better spent on more popular products. 3) They don't know what they're doing or they hate money or something.

And other smartphone companies make foldable phones and not small phones because: 1) Foldables are profitable and small phones aren't. 2) That's not yet true but it's where the market is heading. 3) They all don't know what they're doing or hate money or something.

You're arguing for 3?

A very niche and growing market that 5 years from now will be 80% of all expensive phones.