It really isn't. Apple pays insanely well to exclusively use TSMC top tier node. I would not be surprised if the SoC in an iphone costs Apple 10 times as much as the average android phone SoC.
The “average” SoC or the high end ones in flagships? Don’t be surprised at how much Qualcomm charges for their flagship stuff. Even if Qualcomm is a node behind, they also need their “margin” for making the thing. Apple pays a big design team, but they don’t pay the additional margin on the SoC… just whatever TSMC charges. Remember, Qualcomm has to pay TSMC too.