Many streaming services will split the media file into segments and send only the first few chunks to the browser, to limit bandwidth usage on longer media and block techniques like the one you described. Recently I used youtube-dl to get a zoom recording from Vimeo and remember that it was split in ~35 parts.
It's not that simple for me. If you can show us how to do that (suppose that your audience knows how to use your web browser developer tools, ffmpeg, curl, ...) for a few websites like youtube, udemy, nbcnews.com, ... that will be grateful.