If we're looking at older phones with removable storage, it usually limited what could be put on the SD card. And in the end the OS and system libraries were still on the on-board storage which would wear out over the years.
And there's good reason for the OS not being on a microSD card. Run a Raspberry Pi without locking the storage and see how fast it'll corrupt itself. Most SD cards have pretty miserable reliability compared to the storage on-board. Imagine if you had to re-image your device every few weeks after your storage device corrupted itself again. Not really a great experience.
And there's good reason for the OS not being on a microSD card. Run a Raspberry Pi without locking the storage and see how fast it'll corrupt itself. Most SD cards have pretty miserable reliability compared to the storage on-board. Imagine if you had to re-image your device every few weeks after your storage device corrupted itself again. Not really a great experience.