Ask HN: Video streaming is expensive yet YouTube "seems" to do it for free. How?

Ask HN: Video streaming is expensive yet YouTube "seems" to do it for free. How?
356 comments on Hacker News.
Can anyone help me understand the economics of video streaming platforms? Streaming, encoding, and storage demands enormous costs -- especially at scale (e.g., on average each 4k video with close to 1 million views). Yet YouTube seems to charge no money for it. I know advertisements are a thing for YT, but is it enough? If tomorrow I want to start a platform that is supported with Advert revenues, I know I will likely fail. However, maybe at YT scale (or more specifically Google Advert scale) the economics works? ps: I would like this discussion to focus on the absolute necessary elements (e.g., storing, encoding, streaming) and not on other factors contributing to latency/cost like running view count algorithms.