That doesn't really change anything about the filesystem design. A storage device can fail to write data it claims to have because of damage as well as design d

That doesn't really change anything about the filesystem design. A storage device can fail to write data it claims to have because of damage as well as design defects. When that happens, a reliable filesystem will detect it and a less reliable filesystem will catch on fire. It also doesn't help to control 100% of the built-in storage if anybody can still plug in $GENERIC_USB_MASS_STORAGE_DEVICE and expect to use the same filesystem.