Ask HN: Economics of businesses needing nearly limitless bandwidth

Most tech startups without special bandwidth requirements just use cloud hosting platforms like AWS or Azure or whatever where outgoing bandwidth is heavily metered and relatively expensive, but it doesn't matter much. But there are lots of businesses like Cloudflare or YouTube / Netflix or even shady file hosting sites where the business model requires giving away nearly limitless bandwidth even for the free tier. That means any metered platform like AWS is probably a non-starter unless you have tons of cash to burn or have a special relationship.

Does anyone have experience building a new bandwith-hungry startup without the resources of a mature company behind you? What is your back-of-the-napkin math for how much bandwidth costs you at large scale? How much can you give away and still be profitable with a $20/month-ish product? What do you need to build out to hit that? If the only answer is setting up your own peering, what kind of investment does that take?

Any random stories or experiences welcome. Not expecting anyone to give away their whole business plan or anything. I'm just curious what options exist and if the only answer is running your own racks at a colo facility. Thanks!