@pro @Moon that's probably part of the discussion: where does this system begin or end?
At the point of "download apps outright" we're basically talking about the app stores we already have now packaging containerized apps.
QT is already a cross-platform graphical standard that runs on everything you might realistically use -- so container-image manager, cross-platform standards for interaction/output...
But what about shared data? Intertask comms? All the security fun stuff? Fake UX stuff?