That's definitely true, but I suspect that when you filter down to postpaid unlimited data plans (likely the customers with the highest margins), the iPhone's share of the market increases considerably.
Samsung ships about twice the number of phones as Apple but has a third of the ASP. The conclusion that most Samsung phones are low end is not hard to reach.
But your contract with Verizon or whoever, minus monthly portion paid towards handset, is the same. Not only that, but iOS has a pretty decent install base of older handsets, a significant chunk of iOS's ~45% market share. So even if iOS users did represent higher revenue customers, it would be years and years before optimizing for new intel-derived 5g modems would impact more than a minority of users, while inconveniencing everyone else.
For a currently-possible comparison scenario, are there issues with providers optimizing their networks for qualcom to the detriment of Samsung?