When someone says this, it's a recurring joke, but when I've read your comment, it's the first time I actually think it may happen.
Well, I don't expect a takeover at all, but perhaps I envision something like this year's Reddit migration: I imagine some individuals or companies won't stand for it and switch to Linux.
So maybe in one year Linux on desktop will go from 2% global installations, to 3% or 4% which would be a colossal uptake!
(I admit I've not checked the current percentage of Linux installations, it was 2% years ago, but maybe it's already higher)
Why do you think so?
They could have been threatened by Google or Google might have shown them the correct documents, but how would we be able to tell?