If they really want to reform English spelling, they should write a spell-checking library in every major programming language that builds on every major platform and can be easily integrated into chat, message, and mobile keyboard applications which defaults to “English 20xx”, but still supports default English.
All it would need to do is not highlight “improved spellings” as incorrect in “English 20xx” mode at the start. Then it could slowly turn the knob as they see increasing usage.
If you want to do even more then you can implement speech-to-text and transcript generators that default to “English 20xx”.
But which English 20xx to use? The one that spells the phenomenon of our eyes rendering electromagnetic radiation as "colour" or the one that renders the same as "color"?
Grey or gray?
Is the building adjacent to the one across from you "kitty-corner", "katty-corner", "kitty-korner" or "katty-korner"?
Is the small freshwater crustacean a crayfish, crawfish, or crawdad?
Says who, mind you? Why would facebook adopt some FOSS English 20xx when it could implement it's own for advertising alignment purposes? What are the odds that google and facebook both land on identical implementations?