If the Adobe blog post is correct and the pepper plugin is only distributed with Chrome and isn't open source and part of Chromium then how is another browser going to support it? They'd have to tell you to install Chrome and then open the plugin from within Chrome's installed directory. Pretty ugly solution.
If it's open source and part of Chromium then they can at least take the source out and ship their own, assuming the licensing allows for that and is compatible with their license.
All in all, this sounds like a pretty complex scenario for non-Chrome browser.
Meanwhile, Flash continues to circle the drain, and this might hasten its inevitable, but slow demise.
They might simply shift to Chrome as their default browser.