The iPhone X is in a weird position. It has the "best" tech for an iPhone but it's not as "complete" as the iPhone 8 Plus. Face ID is great. Loved it on my X but I went back to my 8 Plus because I used my iPhone in landscape mode so much. No landscape mode was something I couldn't look past. Touch ID is great but it has its weaknesses (few) just as Face ID. But Apple has the 8, 8 Plus, and X which are all within a few features of each other. Add the 7 and 7 Plus to the mix and you'll see that customers have so much choice to get a really great iPhone at great prices. But I think sales of the X are just fine (when looked at with the 8 and 8 Plus).
The iPhone super cycle will actually be in 2018 and 2019 when so many more customers are upgrading from the 7 and 8 (and X) series to the next series of iPhones.
My ego is gonna pop in here. I consider myself a early adopter. Having the X I can self certify it’s FAR too advanced for most consumers. Apple has 30 years of experience marketing “ahead of the curve” products - the X qualifies. The general market is not ready for no home button yet. Period. Steve Jobs told me last night.