There's a big difference between a video that streams in while the user watches it, and all the styles and scripts that are needed to render the page itself. If

There's a big difference between a video that streams in while the user watches it, and all the styles and scripts that are needed to render the page itself. If the former is too slow the user just keeps scrolling or the player switches to a lower quality stream. If the latter is too slow the user will just close the tab and move onto something else.