With that disclaimer I can safely contend that Google/MSFT will not be interested in this. LaTex is for academic typesetting, with a special focus on math-y content. Even with WYSIWYG, every now and then one will need to get into the weeds of Tex syntax, which is simply not for the average computer user.
As for academia, they will not pay a Google/Microsoft for LaTex use when they might as well use Lyx/Kile or their favorite editor with some syntax highlighting support for Tex. And unlike regular note taking, academic writing isn't so spontaneous that you start editing your IEEE manuscript on the pot, while on your phone.
My guess is that the FAANG tribe have little incentive to commercialize this, and hence acquire it
They have published a list of institutions using Overleaf here: https://www.overleaf.com/for/universities
But the reality is that outside of making office run on other platforms, there has been near zero innovation from Microsoft.