I doubt that anything is really final in google's hands. just look at how fast android is changing and evolving. Google will do what it needs to do to reach their goals, even if it means that they need to break backward compatibility. This is a company with so much resources it can probably design its own reference hardware implementation of vp8 at whatever stage of its evolution, regardless of backwards compatibility - and also persuade chip makers like TI and Qualcolm to include it in their product line at a moment's notice ie within 4 months or so. In this respect, I think the "finality" is overrated - the reviewer / x264 developer is thinking too small.