The point isn't to learn it as if it's something you'll have to recreate--it's to understand that "advanced" language features are built on top of the "fundamen

The point isn't to learn it as if it's something you'll have to recreate--it's to understand that "advanced" language features are built on top of the "fundamental" structural model and are not magic. You need some understanding of how programming languages are built in order to keep languages and libraries honest. Otherwise learning about type/object systems becomes learning all the pitfalls and incidental complexities caused by the design as if they're benefits and not costs.