My intuition matches yours. It's abundant enough to find its way into alloys for jet engine blades at single digit percentages: https://www.thenakedscientists.com/articles/science-features... And if used in chips, you don't need to make the full substrate with this material, just a few hundred nanometers at the top, in the active area.
People don't have understanding of what expensive is. Even at hundreds or thousands of dollars per gram it could be pretty much irrelevant to the end result cost if you only need a layer that is couple nanometers in width.
