The art of large system design is to identify and avoid these kinds of chokepoints. And when something happens, propagate the "backpressure" up the stack to avoid queuing.
AWS got a fair share of similar outages, so the newer SDKs now try to not exacerbate these kinds of issues: https://docs.aws.amazon.com/sdkref/latest/guide/feature-retr...
The original AWS EBS outage is probably the canonical example: https://aws.amazon.com/message/65648/