Neither can humans, but the industry has decades of experience with how to instruct and guide human developer teams using specs.

Usually, you don't want your developers to be coding monkeys, for good results. You need the human developer in the loop to even define the spec, maybe contributing ideas, but at the very least asking questions about "what happens when..." and "have you thought about...".

In fact, this is a huge chunk of the value a developer brings to the table.

Humans have the ability to retrospect, push back on a faulty spec, push back on an unclarified spec, do experiments, make judgement calls and build tools and processes to account for their own foibles.