This is a really good point. Particularly for Twitch, owning their own CDN has turned out to be a massive comparative advantage. From everything I've heard, they've also done an incredible job with relationships and peering agreements over the years to bring costs even lower, and I'm sure that's only gotten better with the weight of Amazon behind them.
That being said, with solid relationships and a little scale behind you, the rate card starts dropping pretty quick. We ultimately use traditional CDNs for delivery, we just switch between those CDNs based on which one is going to provide the best experience for a given viewer. It makes a lot of sense for some teams to build out their own hardware/data centers/POPs at a certain scale, but I think we can all agree that's a decision that shouldn't be taken lightly.
That being said, with solid relationships and a little scale behind you, the rate card starts dropping pretty quick. We ultimately use traditional CDNs for delivery, we just switch between those CDNs based on which one is going to provide the best experience for a given viewer. It makes a lot of sense for some teams to build out their own hardware/data centers/POPs at a certain scale, but I think we can all agree that's a decision that shouldn't be taken lightly.