We know what someone without awareness looks like, we call them coma patients.
The anecdotal stories of people doing things and not remembering them does not mean they were unaware at the moment, it just points to the glitches in the memory processes. Alcohol interferes with ability to record short term to long term memory, among other things. As for driving on “auto-pilot”, it is your brain tuning out all-too-familiar sights and not recording them as not containing any new information.
Your brain is very good at optimizing things, and the more routine-bound your life becomes, the less new information comes in that it considers worthy of recording - if it sees an instance of a pattern it has seen a thousand times, it categorizes that commute to work as that pattern and does not bother recording it unless something out of ordinary happens.
That also explains why time seems to pass faster as you get older - there are less and less genuinely new experiences and encounters coming in for your brain to record and remember as interesting, so time flies by faster and faster.
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.