Maybe HTML 5 isn't ready for YouTube or Hulu, but for people who just want to post a video of their cat on their blog, it is a lot simpler to use the video tag than a Flash solution.
So if people want to post a video of their cat in their blog, they must encode it in 2-3 different formats, and use an HTML5 video player with a fallback to a Flash video player ... as opposed to a single video file and a single Flash player.
Unless those people who own cats are all Richard Stallman impersonators, I don't see how that makes any logical sense.
I don't know about everyone here, but I have nothing but trouble with HTML 5 video (on chrome or firefox). Either it won't play (codec issues I assume), or I can't seek while I watch. I hope it improves.
There's a distinction to be made here though. The reason it's not ready for YouTube is because HTML5 doesn't support things like content controls (e.g. DRM). Most of the videos on YouTube don't have that.
It's disingenuous to say that HTML5 isn't ready for YouTube; it's far more accurate to say that HTML5 isn't ready for content providers. I mean, I can't blame them. HTML5 video in its current state would turn YouTube Rentals into a free movie download service within minutes. Still, the core of what's being uploaded to YouTube is perfectly satisfied by HTML5's current offerings.
Perhaps what would be needed in that case is some kind of encumbered meta-format, one for which codecs could be installed on the local system that would provide the 'content protection' that copyright holders want so badly, without needing Flash as a bloated overlay. It wouldn't be much better than Flash, but it would be a start.
Unless those people who own cats are all Richard Stallman impersonators, I don't see how that makes any logical sense.