Making Firefox even less desirable by "googlifying" it pushes Firefox users away and kills its image of a viable competitor. That's exactly what Google is paying for.
Why would Google destroy the cover they have for keeping control over Chrome and 70% of internet users, just to squeeze a bit more ad revenue from what, 2% of users?
Copying Chrome at the expense of loosing even more of their user share has been Firefox's MO for the last decade. It doesn't have to make sense to be reality.