Over a period of last one year HTML5 specification was becoming popular and there were questions like "Will HTML5 replace Flash/Flex". We have also seen many hot debates on it. But none of such debates went into a solid conclusion.
My view is as follows.
Here a standard is competing with a proprietery technology. This can introduce two major considerations.
1. Accessibility: Being client side technologies, both need to be supported over varying hardwares (Mobiles, Tablets, PCs), operatings systems and browsers. This support requirement always gives an advantage to standard over proprietary. We already have many industry giants aligning behind HTML5. And there could be corporate politics running against propritery technologies.
2. Reusable assets for development: Being a standard, open source communities are excited to develope reusable components around HTML5. Even though the specification is still in draft state, we already have a lot of great HTML5 components in the open source space. This will never be the case with Flash.
So HTML5 should be the final winner. However it will take a few years for the industry to get adopted to that and Flash/Flex will live till that time.
And now, what is Adobe's view on it?
Being the vendor of Flash and Flex technologies, I was expecting Adobe to become more agressive and improve these technologies so that it can give next level of advantage over HTML5. But with some of the recent announcements, it looks like Adobe is trying to adjust to the reality.
1: No More Flash on Mobile Browsers
In Novemeber, Adobe announced that they will no longer continue to develop Flash Player in the browser to work with new mobile device configurations (http://blogs.adobe.com/conversations/2011/11/flash-focus.html). In the post, they clearly stated that HTML5 is the best solution for creating and deploying content in the browser across mobile platforms. So that was a clear answer to the question "Flash or HTML5" at least for the mobile devices.
2: Adobe donates Flex to Apache.
Again in November, Adobe announced that they are donating Flex to Apache community. (http://www.adobe.com/devnet/flex/articles/flex-announcements.html) Well, this could be considered as a positive or negative action. Postitive part is that, if Flex gets into Apache, we will have more enthusiastic committers working for it, along with developers from adobe. As per the latest update, Flex is accepted for incubation in Apache (http://incubator.apache.org/projects/flex.html). Negative part is that, it looks like Adobe don't want to drive the Flex development or roadmap and they may not be investing on it as much as they were doing earlier. And again in Adobe's official blog there is a statement "In the long-term, we believe HTML5 will be the best technology for enterprise application development."
So I believe, Adobe has accepted the reality that, HTML5 will take over the position of Flash/Flex in due course of time.