IRL Example: I host several videos across my various sites. I pay $99/mo for a CDN. Said CDN caches my videos and does not charge for bandwidth usage. Therefore you can technically argue that I pay $99/mo for X visitors. In actuality , the CDN caches all my content. It also provides DDOS protection, a firewall, and other advanced features. That is what I pay $99/mo for.
My cost to distribute the video is $99 + my hosting bill ($50-$200/mo depending on backend jobs) / number of views. This would be true if the video has 1 view or a billion (most of the ones I host have had “millions” of views)
The video can be 360p or 8k. CDN does not care. Mine are 4k.