By all means, if You Are Indeed (Some Reasonable Fraction Of) Google, then by all means, take that seriously. But I can tell you from personal experience I've

By all means, if You Are Indeed (Some Reasonable Fraction Of) Google, then by all means, take that seriously. But I can tell you from personal experience I've been asked to produce a "CDN plan" for content access on the order of once a minute during peak hours, and which had no reasonable business case for distributing enough to matter. I am personally responsible for one system that does need CDN-like capability, because it does serve static files at a rate and a required reliability that a single server can't meet. (We don't use a "real" CDN because for our use case it would be absurdly expensive, but we're keeping an eye on the offerings out there.) So I do know they can exist. But even that system is, in 2022, on the lower end of what you would need such a thing for, and it is serving multi-gigabyte images out on a fairly routine basis to many tens of thousands of consumers (which are automated systems, not humans). That's what it takes to be on the "low end" of blowing out a normal static file server. 15 years ago these systems were a royal pain to maintain, at a much lower level of usage, and non-trivial effort was spent optimizing what they serve. Today, they mostly just hum away doing their job.