I would imagine that no matter how small the operation
    (well aside of operations executed directly by the cpu),
    there's still the possibility to break it up into smaller
    parts.

The scripting system could have been designed to make layering easier. Bourne descendants are ugly and awkward. Hence, unix evolved into a situation where ls had lots of features, whereas were there a better scripting system, we might have had a standard environment which you could introspect deeper and extend with more confidence.