Would Mozilla be able to risk being the browser that can't access Google services? I am not sure that's a realistic scenario for any of the major browser vendors. But arguably if Google's Root CA were never to gain multi-browser support in the first place, they'd never be able to launch their service to begin with.
I don't think Google would "embrace, extend, extinguish" the CA market though as the parent suggested, the CA system gives Google a massive amount of control of the Internet at large, and I can't fathom them giving it up.
I don't think Google would "embrace, extend, extinguish" the CA market though as the parent suggested, the CA system gives Google a massive amount of control of the Internet at large, and I can't fathom them giving it up.