Evolution would not allow waste of energy and complexity for just one on/off switch. Inefficient things die out in the course of millions of years. Neural tissue on itself is far older than humanity, so it had much more time to perfect.
Sorry but that's not how evolution works at all. You are essentially postulating that evolution results in efficient outcomes given enough time whereas there are many, many examples of evolution delivering results but clearly sub-optimal ones. It's not a given that evolution will lead to an efficient solution, it's not even a given that it will lead to a solution at all.
This is an example. Epigenetically driven evolution in arabodopsis, which protects certain regions from mutation. In a very limited sense, evolution might be said to "care" about something here, as it is kind of taking direction from the environment, not simply acting on uniformly random mutations. Nothing like this is known in animals or most anywhere else afaik.