> A lot of beginner guides to various programming languages make this mistake of associating a certain property with a language as if it's inherent. In this case, async code - while sold as a main feature of the NodeJS platform - is in no way exclusive to, or even an inherent part of, Javascript/ES the language.

Exclusive no, but considering JS's original environment and constraints it is in fact pretty inherent. `setTimeout` is part of the core language and has been for a long time, a blocking `sleep` is not.