>We see people here complain every single day about unilateral action taken by Google and the like.

While that's true to some extent, I don't find that to be the case in this specific area (ie. trust store and/or encryption). Are the browser vendors unfairly applying rules (ie. favoring incumbents)? Are their requirements too arduous? Are they not revoking bad CAs? It's not clear what this regulation is supposed to solve.