What I don't get from the article: Why could people in low-bandwith regions suddenly watch YouTube videos? Having the website itself down to 98KB is fine (whic

What I don't get from the article: Why could people in low-bandwith regions suddenly watch YouTube videos? Having the website itself down to 98KB is fine (which still took 2 minutes to load in some areas). But then you only get the first video frame. So then you'd go and watch a video and that file is still the same size (several megabytes at least), which should take them still hours to load the entire video. I understand that less requests and a smaller page weight does matter and I try to keep my webpages as light as possible, but YouTube seems to be the least interesting example for that, since the content itself can't be reduced much further without reducing either the image quality or the screen size.