To answer the question posed by the site. How can they afford 261MB page load instead of 5MB? Because the largest expense of delivering video, the bandwidth, is still very cheap. We're talking less than one cent per gigabyte. Even if ad rates are really low, they're bringing in more than 1 cent per ad play.
This is yet another example of US/BayArea Privilege blindness.
It is NOT cheap in most places to the User. Including in the unprivileged-USA.
The user pays a lot for that bandwidth. Specially now that everyone will unknowingly move to predatory 5G home services but let me try to stay on topic.
People out of the Empire Center will pay both bandwidth and processing power. Where do you think all those old phones you trade in for the latest apple/Samsung ends up? Everyone is running phones that barely gets any security update anymore and is already slowed to the maximum by the OS itself. Trying to load and then display video ads is just evil.
And that is not web only, Apps are worse. If you install Apps, all of them are following the standard set by amazon, newegg, etc... you will get video ads along your usual usage. Ads in between search listings, ads in your cart! and you have to be much more technical to block those.
There's no escape paying the BayArea-cost.