I'd just like to point out that the H.264 issue is way smaller than this. H.264 is a public standard that anyone is free to implement. This is why FOSS encoders and decoders for it can freely exist without any issues (and the FOSS x264 encoder also happens to be pretty much the best H.264 encoder in the world too). The complications arise from the fact that a lot of tech used in H.264 is patented (software) and licensing of said patents is required in many cases to make use of it. But all in all, H.264 is still quite compatible with FOSS (and would be perfectly compatible if software patents didn't exist), whereas DRM is completely incompatible due to its secret nature. This is a far bigger issue for Mozilla to compromise on.

and if they choose to battle for privacy and proper DNT it makes a lot more sense than a losing battle against DRM.

The most annoying part of this is that Abobe is providing the plugin. Much rather Mozilla do their own thing.

This was the last possible moment. Once the web is full of DRMed content, they're entirely beholden to any demands that their DRM partners and content providers might make, like removing the privacy safeguards and giving the binary DRM module full access to the system so it can make sure code outside the sandbox isn't siphoning off the decoded video, extending the DRM to images or even HTML, etc...