You don't even need video for this: I once worked for a company that put a carousel with everything in the product line, and every element was just pointing to the high resolution photography assets: The one that maybe would be useful for full page print media ads. 6000x4000 pngs. It worked fine in the office, they said. Add another nice background that size, a few more to have on the sides as you scroll down...
I was asked to look at the site when it was already live, and some VP of the parent company decided to visit the site from their phone at home.
Many web application frameworks already have extensive built-in optimization features, though examples like the one that you shared indicate that there are fundamentals that many people contributing to the modern web simply don't grasp or understand that these frameworks won't just 'catch you out' on in many cases. It speaks to an overreliance on the tools and a critical lack of understanding of the technologies that they co-exist with.