I can't honestly see how any other company can single-handedly stop Google if they go though with this. Google has the ability to strong arm this proposal by having Youtube and Google search dependent on Web Environment Integrity. There are enough alternative to web search but I can't see how anyone can fight Google's dominance in video hosting to stop them.
You would almost have to have every other major website intentionally break on Chrome to even the playing field, and if Google still don't back down you are left with a divided internet.