Awareness is not binary. My friend going into diabetic coma exhibits a degree of awareness until you realize her answers to my questions have stopped and you have to call the ambulance.
I do agree that the brain optimizes routine things, thus my question is it not possible to function without awareness (ie sleepwalking through life).
I am going from books like these: https://www.amazon.com/Philosophy-Flesh-Embodied-Challenge-W...
Here's a premise: Most(90+%) of our thought occurs subconsciously . Is it not possible function 100% subconsiously?
Think about sleeping on a math problem and the solution coming to you suddenly.