And because of how iPad and iCloud storage is so segmented, if she tries a new reader app it's a massive pain to transfer everything over to the new one. Reading through the docs for one possible replacement app for her and the instructions for managing storage and sync are absolutely horrendous because the simple Apple model totally breaks down in the presence of any actual competitive app market.

Common theme over Christmas with the family is how tech keeps changing for the worse.

Partly I feel them demanding the free tiers of things like Duolingo never change is unreasonable, but they very much are on point with how my sister's iPad keeps deleting local copies of things she's currently reading with no rhyme or reason even when it has loads of storage space available and this seems to have been an issue with the Books app for absolutely years.