Interesting. I would like you to be right on this.
I pulled up 22 CFR and I agree with you that Subpart H would appear to apply to only the 800Mhz services because of 22.905. If there were other frequencies for "Cellular Radiotelephone Service" the would have to be listed. But as you say, here's the puzzle: Where are the current digital services regulated if not in Subpart H? Originally of course, the FCC has used "radiotelephone" to refer to analog services. (Certainly that was the case back when I got my First Class Radiotelephone license -- there were no digial transmission beyond Morse code! Of course that license allowed me to operate and maintain televison transmitters as well, so not quite "telephone.") So maybe current cellular technology is called something else and handled outside Subpart H? I dunno.