Joking aside, more typically the server you never heard of will be something in the CSP’s control plane.

But that’s just a distraction. We hear about those outages once in a blue moon, because many rely on them. What we don’t hear about is that any given colo, managed service, or CSP customer’s apps go down on their own, all the time, not because of the colo or CSP.

Such outages are banal, so we forget how much more likely they are, and fail to risk-weight our engineering efforts accordingly.

Redundancy isn't the only reason to make a system distributed. There's also latency, cost to scale, and federated management. DNS is very distributed but redundancy is opt-in.

Many distributed systems try to be reliable by retrying failed nodes' work, but designs aren't always sound.