Have you ever built a service designed to operate at planetary scale? One that's built of hundreds or thousands of smaller service components?
There's no such thing as infinite scalability. Even the most elastic services are not infinitely elastic. When resources are short, you either have to rely on your customers to retry nicely, or you have to shed load during overload scenarios to protect goodput (which will deny service to some). For a high demand service, overload is most likely during the first few hours after recovery.
