What matters here is the communication overhead not how long between responses. If I’m indefinitely spending more time handholding a jr dev than they save me eventually I just fire em, same with code gen.
Most people do get better over time, but for those who don’t (or LLM’s) it’s just a question of if their current skills are a net benefit.
I do expect future AI to improve. My expectation is it’s going to be a long slow slog just like with self driving cars etc, but novel approaches regularly turn extremely difficult problems into seemingly trivial exercises.
That said, you are underestimating AI costs if you think it works out to a fraction of a cent per hour.