On the contrary, if Firefox market share were to grow then Mozilla would only be in a better position to negotiate with Google. And the fact they support a rival with a larger share would only strengthen the argument that Google is not monopolistic.

Don’t lose sight of the fact that Google’s main concern is Search market share, not browser market share. As long as Mozilla agrees to keep Google Search as default Firefox could have 90% market share and Google would still be ok with it.

It’s true that browser market share also counts indirectly, because it allows them to influence the technology. If Google rolls out support for something, or withholds support for something, it affects everybody and can make or kill any particular piece of tech.

Browser engine dominance will come under scrutiny but later. Right now it’s about Search.