Sales don't really pick up until a few months later. I remember I saw only 5 iPhone X owners including my Brother the first two months. After six months, I saw the X everywhere including celebrities using it on TV.
The early adopters are getting the worst batches for it anyway. Bugs and rushed models. The early bird doesn't always catch the worm but a lemon. Some people just wait for Black Friday or whatever Slickdeals they can find.
I agree with Matthew Moniz. It's pretty much that maybe people are getting tired of upgrading their phone and spending so much for it. The market is saturated as is. Will it even change your habits on how to use them? Not really.
Last year, more people waited for the eXpensive model for the new design. Now people are waiting for the cheaper model with a similar design. In some ways, all mobile brands became McDonald's.
The smartphone fad is dying. It's getting to a point that I know more people still using an iPhone 6 than owning a X.