YouTube's definition of 'High Quality' has changed since it first started giving a 'High Quality' option on it's videos. Or at least I thought it did.
Back when I first started using YouTube in 2007, 'High Quality' didn't even exist. You were lucky if your videos didn't look like a pixelated mess half the time. Early online video looked poor, anyway... and it took way too long to watch it. While YouTube fixed the issue of download time with Flash, the video quality was still considered bad by today's standards. Eventually, with higher speeds of internet connections, people could download better quality videos much faster. YouTube had to keep up with the times, so they made higher quality an option. Then later, YouTube crossed into the HD era.
The point I'm getting at: when I purchased a new video camera and video editing software a few years back, I wasn't even thinking about HD. I was thinking about the highest possible quality for YouTube videos at the time, where YouTube recommended a resolution of 480 x 360 for 4:3 (standard) ratio, and 640 x 360 for 16:9 (widescreen) ratio. This doesn't cut it anymore. The minimum for 'HD' is 720 pixels in height, which my current camera and editing software is unable to create. On the bright side, at least I have a computer that can watch 720p and 1080p videos correctly. It can even run those '4k' videos rather smoothly (though they don't look as good as the 720p videos on my monitor resolution).
And then, there was a confusing time where we were trying to figure out what triggered the 'High Quality' option. Just before YouTube made 16:9 ratio it's standard player size, they recommended 640 x 480 as the standard resolution. These appeared in 'High Quality' fine, but in the switch to widescreen, I was uploading 640 x 360 videos, which didn't get the 'HQ' option. At least now, I think I know the problem was the height of the video.
I currently can't create a Widescreen video that goes any higher than 360p on YouTube, so I think the editing software is the first thing I need to update. Even with an HD camera, it's not much use if the maximum resolution of video I can save in my editor is under 480p. It's also possible that I can still use my current camera equipment, as I think the most important part right now is being able to save my projects as larger resolutions.