This reminds me of the arrival of the PC (MS-DOS and Mac): file formats were typically silos: proprietary and could only be opened in their special app. Coming from a different tradition this was completely weird and uncomfortable to me so I never really got into those systems. Gradually some open formats pried this open: GIF/JPEG/MP3/ZIP (all only somewhat open at the time) then turning into PNG/HTML... etc.
In this regard the phones feel like a step backwards as each app really manages its own data. Email programs these days are like that -- for example you can't keep a project's mail folder with its files any more.
Back in the early Windows days, I was helping somebody on Windows get some data somewhere else where I needed it. I started by opening the file manager and finding the data files. He was like "Whoa ... you are in no-mans-land" ... he just wasn't familiar with accessing files outside of an application.
There are a couple of orthogonal concepts are work here a) how data is stored, in files with a well-known format, in files with a proprietary format, or perhaps in some kind of database b) who has control of the data, perhaps defined by who would be able to delete it, or whether the data would cease to be accessible if a particular organization ceased to exist.
In this regard the phones feel like a step backwards as each app really manages its own data. Email programs these days are like that -- for example you can't keep a project's mail folder with its files any more.