Actually the iPhone X is selling so poorly that Apple has not only cut production, they are rumored to be dropping it entirely this year. The technologies in the iPhone X will apparently be distributed across three new iPhone models.
I had kind of always assumed that the X was a special edition phone anyway, and it was going to percolate into the other models eventually anyway. And it's always good practice to take these "analyst" reports with a (massive) grain of salt.
I have an X. Did not plan on it. No way. Have a 6P for years. Went in to T-Moble to get my wife a new phone. I was thinking about getting an 8, but... then the guy said, hey it's a few bucks a month + $300 credit for your old 6P and it includes Apple care. So I got an X for what I would have paid for the 8, and I am using their money interest free. Worked out well.
Also, surprisingly I love the phone. Camera is amazing. The faceID thing does not suck.
I tend to be skeptical of such analysts, though. Not that the ultimate claim of "the iPhone X's advances and form-factor are going to be moved into all the other models" is terribly controversial -- that's pretty literally what Apple said would happen. Just that it's a person guessing, and such things have been fairly spectacularly wrong in the past.
So are they dropping “it”, by which I assume you mean the FaceId tech, or are they rolling it out to the other phones that Apple sells? Your statement contradicts itself.