In my experience people choose iPhones because they are a status symbol, and because Apple has become synonymous with good design and good taste. Due to marketing efforts, Android devices are still seen as the "cheap option" or for people who don't care about their image. Many people are also already locked into the Apple ecosystem through desktop/laptop Macs, iCloud, etc., so getting a non-Apple phone would introduce a lot of friction into their experience.

Part of it is also that iOS used to be quite far ahead of Android when it came to usability and polish. Android has since mostly caught up, but there is an advantage to being a first mover, and the people who didn't like Android back when it was much worse have since gotten locked into Apple's ecosystem, even if they never used Apple products before that.

I don't think most people seriously think about App Store curation as any of top reasons why they have an iPhone.