> proven reliability

This. I buy iPhones because I know that every released version will be bought by several tens of millions. I don't want a smartphone that only a couple of million bought. If something is wrong with it I don't want to find a few unhappy souls on some forum complaining about the same thing, and a manufacturer that's already pushing ten new models. The "Just works" feature is worth so much to people.

Obviously some of the the flagship android phones are also big sellers, and also tend to "just work" - but those also cost about the same as the iPhone.