Even in the case of video, where Flash is enabling over 75% of video on the Web today, the coming HTML video implementations cannot agree on a common format acr

Even in the case of video, where Flash is enabling over 75% of video on the Web today, the coming HTML video implementations cannot agree on a common format across browsers, so users and content creators would be thrown back to the dark ages of video on the Web with incompatibility issues. Not really. Most of that 75% is in h.264, a format supported natively by every browser/platform that doesn't support Flash (e.g. iPad) and some that do (e.g. Chrome). Even Microsoft, if and when they do implement <video>, are likely to support it. It may be messier than just assuming Flash is available (welcome to web "standards"!), but I would hardly call it "the dark ages".