The logic seems to be that if Firefox supports EME, that movie producers will be able to switch to using it without business pressure to release completely DRM-

The logic seems to be that if Firefox supports EME, that movie producers will be able to switch to using it without business pressure to release completely DRM-free versions of media. It's an argument I'm partial to myself, having run a Linux box for more than a decade, but it's still an argument based on self-interest.