How would that work in practice? By its very nature open data would also be accessible to proprietary programs although the reverse need not be the case.
Seems like we will need open data and code. Either one open will not do.
That is a good thing. If program X works best on my data I want to use it. There are a few examples where people do mix programs from different companies. Musicians use MIDI to connect their favorite keyboard to a synthesizer from a different company all the time - sure it is tied to hardware, but it need not be and is a perfect example of what should be possible for any user data: mix and match.
> although the reverse need not be the case.
It doesn't have to be, but if users demand it, it will be.
> Seems like we will need open data and code. Either one open will not do.
Open data means we can create the code. Closed data is a lot harder to deal with than closed code.
When your data is complex, the processing done to it will be complex, especially if you need to guarantee invariants (eg. referential integrity or database constraints).
Edit: I envision it a bit like streams of data that you can subscribe / push to. Think RSS mixed with a pub/sub type of model. You would subscribe to the hackernews datastream, and submitting articles and comments are done using push. The push message would have some predefined metadata fields that are obligatory (article url, title, summary or comment text).
Can you imagine if Android licensed iMessage instead of building Hangouts? Yes, we’d all be texting on the same protocol, and yes we’d have a choice of clients, but at what cost?
The real problem is who owns your data. Because if you use Word or Photoshop, your files are locked inside Word and Photoshop. And this is still true if you use FOSS alternatives, because there's only very limited support for metadata-aware sharing between applications of all kinds.
It would be super-useful to have (for example...) seamless links between text editors, web design applications, web hosting systems, and even video editors and ebook publishing tools. But that's not where we are now. There's some limited interchange, but most cross-domain transfers are difficult and fragile, and some are impossible.
Cloud is just the online version of the same model. When you have proprietary control of user data through proprietary file formats which actively frustrate open sharing of data between applications, it doesn't matter of the data is stored locally or in the cloud. It also doesn't matter if you're using a mobile or desktop UI.
The FOSS people have always been looking through the wrong end of the telescope. The real revolution would be open data which is wholly and exclusively owned by users (or user groups for collaboration) and loaned to proprietary software for specific limited tasks.
Which is the opposite of things work now. Applications and products own your data and they let you access it - but only if you ask them nicely. And - increasingly - if you pay annually for the privilege.
So containerisation or self-hosting or whatever is a non-solution unless it also gives data back to users.
Which is also why the fragments idea won't work. There's limited use in trying to automate or manage or otherwise AI-ify access to data that you don't truly own anyway.
In fact a new kind of shared Internet would be a very useful thing. But it would need a ground-up redesign of everything, including browsers, mobile apps, desktop applications, operating systems, search, and the financial and legal frameworks surrounding them.
I'd love to see that happen. But right now in 2021 it just doesn't seem likely.