Google has become this unwieldily beast that doesn't care how frustrated its users become, because it knows not enough of them will leave to have even the slightest dent in their revenue.
Never really thought about it before but Google definitely has the video market locked. Vimeo, dailymotion, liveleak, et al don't even come close in terms of content.
And if you do have a Mac built in the last 4 years, you're not missing much by using Flash. Difference in CPU usage is negligible and I haven't used an in-browser HTML5 player that wasn't shitty compared to its Flash implementation.
The negative of non-Flash movies (YouTube has some) is that they auto-play. Few things annoy me faster than sound coming from a background tab. I generally close them immediately (I usually queue up stuff to look at).
It's interesting, though. In Hollywood, Vimeo seems to be the default choice for professional work. Up and coming directors have their short films and reels up there. And there are some password-protected videos top pros use for work on very big name films.
It's weird how markets segment like that.
Thus if you find a link to a video on Vimeo there's a good chance there's some semblance of quality. Especially if it's a gaming video, because they do allow machinimas. They fostered that artsy niche and in the process became something totally different from YouTube.
There are a dozen news + comments that all have a slightly different threshold for what stays on the site, determined by the tastes of the community.
Why haven't more video sites emerged with a similar ethos?
Because if they touched commercial music or video at all (even by accident or if it's fair use), they'll be sued into oblivion and/or asked to implement the same level of "content protection" YouTube has today (effectively the same thing because a startup video site wouldn't have the resources for that). Remember, the only reason YouTube exists today in any sort of recognizable form is that they got together with Google's checkbook and Google's lawyers. That gave them the legal ammunition to force some kind of settlement (albeit a deeply flawed and problematic one, between ContentID and non-DMCA takedowns, among other things).
If a YouTube competitor is going to emerge, it's going to come from a big company. That's not impossible, but most (all?) of the likely candidates would bring their own (similar or different) serious flaws to the table. And even then they'd need to develop a "content protection" scheme roughly as good as YouTube's - which would take serious machine learning chops on top of everything else, whittling the list even further.