Sure, but there's plenty of software that's written to use distributed unreliable storage similar to how cloud providers write their own software (e.g. Kafka).

Sure, but there's plenty of software that's written to use distributed unreliable storage similar to how cloud providers write their own software (e.g. Kafka). I can understand if many applications are just need something like EBS that's durable but looks like a normal disk, but not so sure it's a fundamentally required abstraction.