Is it though? It is static content. A good CDN could trivially chew through literally millions of QPS… with 4 nines of uptime - the really good ones say they can handle orders of magnitude more than that.

Notice I said for a few moments. In a few hours traffic will drop a few thousand percent back to normal with no need for a CDN.

OpenAI isn't making any money telling you about Astra on their site. All the capacity they have for it is likely sold for weeks or months.