People tout "open standards" and "open source" as being the utopia of software development eco-systems, as if the benefits are so self-evident that they require no further explanation. But I have not encountered a convincing argument for why this is. Sure it fosters collaboration and is more 'democratic', but it also results in fragmentation, competing implementations, and responds too slowly to changing trends and technology.
As you're already aware, HTML's wonderfully democratic design-by-committee has given us a web platform that took nearly a decade to even acknowledge web video after the fact, and has still not agreed on a video format. Its given us a fraught development process where we must painstakingly account for the bugs and differing implementations of half a dozen browsers.
If you want to bring that kind of environment to a Flash type platform, I don't think you'll have many takers. The reason Flash was so successful in the first place is precisely because it was proprietary and controlled by the "whims" of a single corporation. It turned out the "whims" of this corporation were actually the whims of web developers everywhere, and allowed them to bypass the decades that would go by before the W3C could shape HTML into something that would respond to current needs.