You're right, Node.js has no concurrency primitives, but it has true first-class functions.
Ruby lambdas are an afterthought and far too expensive to use in the same expansive capacity as you would in JS (or literally any functional programming language).
Couple that with the fact that the community just doesn't care, and again, I ask why bother?
The actor model isn't superior to callbacks in any technical capacity, and understand, callbacks are only a (perceived) problem when you don't have something like a language-level async/await to transform them for you.
edit: Add in the (MRI) GIL, and you've got yourself a fairly serious impediment to writing efficient, concurrent code.
Ruby lambdas are an afterthought and far too expensive to use in the same expansive capacity as you would in JS (or literally any functional programming language).
Couple that with the fact that the community just doesn't care, and again, I ask why bother?
The actor model isn't superior to callbacks in any technical capacity, and understand, callbacks are only a (perceived) problem when you don't have something like a language-level async/await to transform them for you.
edit: Add in the (MRI) GIL, and you've got yourself a fairly serious impediment to writing efficient, concurrent code.