The thousand dollar iPhone is the BMW 7 series of iPhones. Apple at this point is constrained by their supply chain. They have the capacity to introduce new tech, but the tech isn't capable of being produced at the scale to put in a couple hundred million iPhones, so they put it into a more expensive phone and sell fewer of them. Then they put the tech that works into the regular iPhones a couple of generations later when the supply chain matures. Seems like a good long term strategy.