Based on my experience I think a universal solution will have a starting point in the individual and will evolve from something like obsidian or emacs (but it will probably never evolve from a consumer hostile community/platform like emacs)... and will eventually be akin to a full OS replacement.
For any given universal interface you have to make it extensible, interoperable and personal (for some given definition of personal) and no software organized around a group can get there without a fundemental rework.
Honestly, I think for large commercial players (products like MacOs) it's more likely for us to get there after AI conversational interfaces are fully synthesized and OS' are fundementally reevaluated for production after they lose their relevance in other general computing ways.