The only thing that keeps Adobe from completely open-sourcing their own player is codec licenses, not Adobe's stubbornness. Adobe pays a lot of money to license codecs that are closed (like h.264) and therefore have to protect those interests within their player. If there were a common open standard for video/audio, this would be a possibility.
(edit) http://blogs.adobe.com/open/2010/02/following_the_open_trail...