Highly scalable systems have to be designed in a particular way; it's an architectural concern - Your choice of language might make it somewhat easier to implem

Highly scalable systems have to be designed in a particular way; it's an architectural concern - Your choice of language might make it somewhat easier to implement a highly parallel architecture, but the language itself will never make it 'easy' - Languages will always give you just enough rope to hang yourself (that is the cost of flexibility). You could design a framework which is extendable and scalable in such a way that developers who want to write code on top of that framework don't need to think (much) about parallelism (see https://github.com/socketcluster/socketcluster#introducing-scc-on-kubernetes https://github.com/socketcluster/socketcluster#introducing-s...). Unfortunately, you cannot build a highly scalable system without enforcing some rigid constraints. General purpose programming languages do not enforce restrictions on what design patterns you can or cannot use use; that is the role of a framework. That said, frameworks can never fully hide the complexity of parallel systems (not for all use cases) but at least they can guide you to the best approach when solving specific problems.