Make?! Are you serious? It already is. Currently Firefox is just using Flash to play h.264 videos, not OS codecs. There is little practical difference between those two things.

This was always about booting h.264 from its position as the standard for publishing video on the web.

For h264 to be enabled in Firefox, you must already be using a mobile device or in the future an operating system that (financially and technically) supports non-free codecs.

Is there a remotely modern video codec that isn't encumbered? Just because it is offered up as free software or open source doesn't mean that someone else's patent doesn't already cover it.

I have no faith that WebM is non-encumbered. The real issue is our patent system, not codecs.

The patent system is so that almost every non-trivial software can be considered encumbered. Yet the chances of being sued successfully are different. Why will MPEG LA need to push their codec if they could profit from selling patent licenses to WebM users?

I suspect that the real motivation of the H.264 supporters is that the patent encumbered codec will allow content providers and proprietary software vendors to control who is allowed to produce video playback software (at least, they could make it impossible for free software to support the codec), and impose mandatory content protection. That will make the content industry giants closer to their ultimate goal of eliminating all the culture they do not control.

Is that really such an issue? For a highly published patent like that I am sure some prior art can be found, if necessary.

If it were so simple, someone would have done it already. In reality, you're talking about a massively expensive legal battle with an uncertain outcome.