[barumi]

> Even though they're technically different concepts, I've found in practice they're almost always coupled together.

Not really. Event sourcing is typically implemented with CQRS, mainly due to how ES relies on streams of command messages and as CAP-related requirements already require mutable and immutable commands to be processed differently. However, CQRS has zero requirements other than segregating interfaces.

Hell, in languages like C++ you already get CQRS out-of the-box by following const-correctness.