I disagree that linked lists are obsolete; they are fundamental to the history of computer science, are still widely used (e.g. the linux kernel is full of them), and are still useful in some niches (e.g. mutating a container while iterating over it)
car/cdr however, were assembly instructions for an obsolete architecture that never should have made it into a high-level language. (let alone the abominations `cdaadr` et al) but some folk value algorithmic purity over pragmatism.
