I'm scared to calculate how much it would cost to run YouTube off of that.

Many years ago I remember that YouTube reported that 24h of video was uploaded every second. This means that your storage cost would increase by $432/s or $37M/d. This means that you are paying 14B/month by the end of the year just for storage.

Of course there are a number of factors that will work in your favour here: - You can attempt to focus on only hosting "popular" content instead of allowing anyone to upload. However this can make it difficult to draw new creators to the platform. - You can definitely negotiate a better rate.

However I'm still under the impression that if you want to create a YouTube competitor you are probably better of starting with lower level components so that you are in a position to reduce costs for old and low traffic videos. My impression of Cloudflare Stream is that it is aimed for people sharing a relatively small amount of content (probably just their own).