You did say practically, but I’m saying that practically is still a cost. You are still paying money to serve your videos.
People post on YouTube because they don’t have to pay the server costs for videos. If you want to get the video makers to pay the server costs, feel free. However, given their thin margins, they probably won’t.
Also, it sounds like your CDN is betting your videos won’t routinely go viral and get billions of views. If that happened, I would expect your monthly bill to go up.