Fair enough. The app centric approach is done over the cloud so you won't loose stuff if you delete the app. I agree iOS does need to evolve and it is a lot but I still think a file system is not needed. The tech world for the most part has moved past file management and local storage, especially on mobile devices. I used to have the nokie N96 and N97 (symbian) and used to think the file system was awesome, looking back now I think its so old fashioned.
Its just different times with everything being app and cloud centric. Even on my mac I hardly use finder anymore compared to say a few years back.
Having folders and an exposed file system (which you sort of can do with iCloud drive) is for the minority. Im not saying i wouldn't appreciate the feature they way you illustrated tho.