It’s a high-end form factor; it’s not supposed to compete with far simpler, primitive phones in sales. Foldables are expensive and hard to manufacture; they cannot scale to mainstream numbers of a budget phone.Not naive just look at the market share of fold phones.
Not everything needs to be for mainstream users to be worthwhile. You think high-end/prosumers of 5090s, Threadrippers, and Porsches care most cannot afford or justify it?
Do you buy products based on marketshare or your specific needs? Unless you’re a pure consiker who needs others to create content tailored to a device for it to be useful to you (nothing wrong with that), it’s usually questionable to care about the former.
Apple has a portfolio of products in which the higher-end products trickle down features to lesser and more modest featured devices.