I don't think this is true, Apple has definitely been raising prices significantly in the last few years even on the cheapest models. Unless you're counting still being able to buy a generation or two behind for cheaper as "current generation"

Edit: this article has a nice chart https://www.gsmarena.com/price_history_of_apples_iphones-new...

There's a couple of blips with the 5c and the SE but for the most part even the "budget models" are more expensive than the flagships of old, and the flagships are significantly more expensive.

I'm curious how long they can continue this and still sell phones. I wonder if prices being spread out along 24 month contracts with carriers is what's protecting their sales despite the price rises.