I doubt Google wants to keep this Chrome-only. Just like SPDY, there isn't initially support on all platforms/browsers so you have to have a fallback. But if it catches on then you will see broader support over time.
Having taken a good hard look at adding this to a non-chrome browser I can tell you it would not be a trivial task. You can't just take the code and re-use it elsewhere and re-inventing it would require constant catch up.