That logic might work for firefox's product direction as a whole, but narrowly looking at the EME issue, what should have they done? If they didn't implement EME, then people will have to install chrome to watch netfilx. The users who are there as a matter of principle (eg. HN readers) might still use firefox as their daily driver, but they'd almost certainly lose some normies who were using firefox on inertia. Meanwhile because they refused to negotiate, they won't be able to influence the direction of the standard, which means no sandboxing of DRM modules and other privacy features. Both firefox and their users lose out in this scenario.