Jason Snell, writing for Macworld:
This is one of those areas where Apple may be the victim of its own success. The iPhone is so popular a product that Apple can’t include any technology or source any part if it can’t be made more than 200 million times a year. If the supplier of a cutting-edge part Apple wants can only provide the company with 50 million per year, it simply can’t be used in the iPhone. Apple sells too many, too fast.
Contrast that to Apple’s competition. On the smaller end, former Android chief Andy Rubin announced the Essential phone, but even Rubin admitted that he’d only be able to sell in thousands, not millions. Same for the RED Hydrogen One — groundbreaking phone, hardly likely to sell in any volume. The Google Pixel looks like it’s in the one million range. Apple’s biggest competitor, Samsung, has to deal with a scale more similar to Apple’s — but it’s still only expected to sell 50 or 60 million units of the flagship Galaxy S8.