Could h264 support be added to Firefox with a plugin? Windows and Mac OS have the ability to natively play h264 videos, perhaps there is a way for FF to hook into that and not have to worry about any h264 licensing fees.
No, they belligerently designed their <video> and <audio> implementations to make that incredibly difficult to do without forking the whole project.
They link directly with liboggplay instead of using a library like ffmpeg (Chrome), gstreamer (Opera), Quicktime (Safari), or DirectShow (IE, eventually). They don't even support any other container formats! I hope their heads fall off.