The Wall Street Journal “confirmed” rumors that there were some production glitches early in the summer, and then essentially guessed that nothing has been done in the months since then to catch up. If so (“If pigs could fly’), then the phones will not be available on the launch date. That rumor has a core of truth: they will be in short supply, of course.
When has there every been a glut of Apple inventory on launch date? The company sets a production schedule that does not waste a lot of money by overbuilding the production lines for the initial surge, or by filling the supply channels with surplus devices in configurations that may not sell. It waits to find out which models, configurations, and colors are popular before making midcourse corrections to make those devices in larger numbers.
The reason that this device has a premium price is to limit its appeal to people who do not really need a premium phone but might overwhelm the available supplies by ordering one anyway. That will (1) make the wait for the SuperPhone tolerable while (2) shifting a considerable number of buyers to the mainstream iPhone 7s (or 8, or whatever they call them), and (3) increase Apple’s margins.
Source : http://macdailynews.com/2017/09/07/apple-shares-dip-amid-report-of-iphone-production-delay/