there was no notch before because of the large bezel on top..
on the X, there's a small bezel up top which was made even smaller by notching out the sides of it and adding more display..
the notch isn't because of FaceID.. it's there because instead of making the X bezel go all the way across, they made it only half as wide and added status info on the left/right via more screen.
where are you getting this from?
previous phones had a large bezel so they could get away from the rounded corners of the phone/casing and fit a rectangle display in there.. now, they can cut the corners of the display and better control the pixel curvature.. so they did just that and were able to eliminate most of the bezel..
look at that picture i posted earlier.. the fattest single component is the faceTime / front facing camera.. the bezel has to be as thick as it is in order to accommodate that non-faceID element.. if they got rid of trueDepth, they couldn't shrink the bezel anymore.. all they could do really is make a skinnier sensor housing with a wider area for status info..
but definitely still notched and at the same height.
anyway.. a more detailed explanation of the X design can be found here:
https://forums.macrumors.com/thread...tisfy-plus-users.2075344/page-8#post-25188041
(at least, my personal understanding of it)