Doesn't seem to address the elephant in the room: that Apple, Nokia and Microsoft rejected Theora as a lowest common denominator fallback codec, and failed in their efforts to convince the relevant patent-holders to make Baseline H.264 available for use on the web and now are stonewalling WebM just because it doesn't suit their business interests.
I'm fairly certain the other stuff would have fallen into place if a codec was widely supported.
edit: actually I suppose this is covered by "browsers failed to support WebM as well as they support GIF." but it's confusingly worded since Microsoft and Apple basically don't support WebM at all, and the widespread usage that leads to a better interface (in the browser and in forum software) depends on that.
A bit of the trick and appeal to animated gif is no sound (at all) and (typically) low cruft: it's the 'money shot', looped. no padding, no channel begging, optimized for download speed, no buffering, no pop-ups, no ads, no captions, etc.
I wouldn't mistake its prevalence as evidence of any failing of <video>. When people -want- video, they know how to post, embed or share it. While geeks care about plug-in-free video, the people sharing animated gifs do not.
The use case for animated GIF isn't video even if it's been pressed into that function. Even in 2013 I've evaluated the options and ended up using an animated GIF on new pages[1][2]. It's the simplest tool available to do an animation, not a video. It sucks as a format though with it's poor color handling and lack of compression.
Ideally I'd replace those GIFs with a bunch of JPGs and a touch of javascript to cycle between them. It would even allow me to have the animation only start when the image is first visible, whereas now it just cycles indefinitely. But all that would require a bunch of work and the animated GIF was easy to create.
PS: I need to go pester the posthaven guys to implement auto cycling of photographs in their galleries to replace the ugly GIFs.
I'm fairly certain the other stuff would have fallen into place if a codec was widely supported.
edit: actually I suppose this is covered by "browsers failed to support WebM as well as they support GIF." but it's confusingly worded since Microsoft and Apple basically don't support WebM at all, and the widespread usage that leads to a better interface (in the browser and in forum software) depends on that.