too expensive for there to be competition

How does that work, exactly? For something like a railroad or a power grid, you get a natural monopoly because you need a system to connect everyone to everyone else for it to really work, and you need to pay to build out the connection to each person.

For video streaming, you need to pay for servers to transcode, store, and serve the video. Which is expensive, sure. But then each user comes in over the Internet; you aren’t paying to connect directly to their house, and you aren’t putting a CDN node in every town when the town has 5 users who can just talk to the central deployment.

If you want to run ads, you find some network that places video ads, and you get the ads from them and you run them. Maybe they don’t pay enough and the service is not profitable, but what would make that change if the service were bigger?

Where are the huge, unassailable costs? Where is the revenue you can’t get unless you are the absolute biggest?