Low effort modularity would be so easy... Back when smartphones were not phablets and batteries were swappable, custom back covers for fat extended batteries we

Low effort modularity would be so easy... Back when smartphones were not phablets and batteries were swappable, custom back covers for fat extended batteries were available for almost any device. That's one precedent. The other are Wi-Fi SD cards that were sold before digital cameras started to integrate Wi-Fi on their own. There is another. Custom back covers for the minority who needs extra space and few connectors in the form factor of wired microSD (because micro USB is specified with far too strong mechanical reserves for this use case) would come at near zero extra bulk for those who don't use those possibilities and the minority who does have exotic needs would still be served. Everything that would be used by more than 5% of users should still be integrated, everything else would be a waste of resources because high numbers have such a strong effect of making electronics cheap and light.