I absolutely don't have that expectation. I built a comic reader app that I use on my Android tablet, which saves files to IndexedDB. I've been using this for o

I absolutely don't have that expectation. I built a comic reader app that I use on my Android tablet, which saves files to IndexedDB. I've been using this for over a year and no files have ever been deleted, even after I stopped using the app for a month or so. If Apple provided an alternative this would be ok. An alternative such as the native file access API (still a WIP). Or a prompt so that the user can allow long-term storage. Or supporting the web app manifest so that users confirm they want to "install" a web app, granting it greater permissions. But they've offered no alternatives here, that I can see. They've determined that client-side web apps are simply not important.