> for h.264 they did stand up and lost.

You might argue they lost the battle but won the war. A technological split between traditional media companies and web companies has developed: the former are continuing to pursue MPEG-LA endorsed codecs that enable their industry to keep a stranglehold on the market (i.e. H.264, HEVC, VVC), while the latter have moved to alternatives: a lot of hardware comes with VP9 decoding support already, and there's an enormous push (with nearly 100% buy-in) to make AV1 the web's next default video codec.

This means that the web is moving towards media streaming on mostly royalty-free codecs, which was exactly the goal Mozilla originally had.

As a point of interest, Google had announced that Chrome would not be supporting H.264 around that same period, but then backtracked and never removed it.

Edit: IIRC, it may have been the built-in support/licence for H.264 on Windows and Macs that kept the support in Chrome, so those running Chrome on other OSes might not have been so lucky.