Screen replacement, camera, DSP and audio out, radio, sensors, USB port, all could be upgradeable or at least, replaceable to fix breakage. Yes the phone would

Screen replacement, camera, DSP and audio out, radio, sensors, USB port, all could be upgradeable or at least, replaceable to fix breakage. Yes the phone would be bigger, but I believe the main reason this has gone nowhere is that people have got used to seeing phones as replaceable units at the phone level, not at the component level, and there's more money in selling a shiny new Galaxy Over9000 than there is in selling a swap-out for a busted screen.