I think you haven’t considered the luxury goods aspect of higher-end phones. The majority of people buying new phones every year or two don’t carefully study specs, and don’t need to use a PC or laptop at all, or only need a “real” computer for work or specific tasks. Already smartphones serve as the primary internet access device for a majority of internet users. Sales of new phone models have a lot more to do with…
There are upper-middle class equivalents of this. Cars come to mind.
It is interesting explaining to a middle class person why I have a $100 crappy phone. "My old one broke, and I have 4 of these $100 phones for my wife's company, so I'm using it until I find a good phone with an Aux port". Ease is everything.