[tgma]

It's not a question of possibilities. It's a question of trade-offs. It just does not sell (or at least hasn't.) Integrating everything often equates to less cost, less weight, less materials, less power use, less thickness, more reliability, more water resistance, more performance etc. for the vast majority of the users who have voted with their wallets. And to a nontrivial degree there are physical constraints that dictate this not just marketing and R&D spending (do you want to have replaceable SODIMMs in your iPhone?) I bet the average user likes the idea of modularity and user serviceability but wouldn't want to pay $100 extra for modularity in their $1k iPhone. They are likely more willing to purchase peace of mind through insurance, ala AppleCare+, than to purchase serviceability.

But sure we can keep pretending modularity is free and therefore of obviously a nonnegative option value to the user.