That is definitely an interesting question you ask. It can become an expansive conversation very quickly; however, I do have a few thoughts. First, I am curious how you define subconscious and/or unconscious? That may help to focus the direction of the conversation.
Second, as a behaviorist I lean toward eliminating all terms that describe mental processes in metaphorical or analogical terms. Terms like the subconscious, the id, the ego, self-efficacy, resilience, narcissism, memory bank, etc. I do think they have utility – as long as we recognize that they are constructs that describe a phenomena and are not real “things” that exist. They describe a set of operant behaviors that can be somewhat slippery to define because they are most often covert.
Skinner wrote a good article entitled, “Why I am not a cognitive psychologist” that explains mental constructs in more detail. The first half of the article is a bit pedantic, but you can skip to page 9 for the main point of the article. So in conclusion, I guess my answer would be that I do not believe that as humans we possess a subconscious/unconscious. I think “what we do” that is typically ascribed to our subconscious can be explained through our operant behavior that has been shaped by our environment. At least for now I believe that. Who knows, maybe subsequent comments will change my mind. I have included the link to the Skinner article if you or any one is interested in reading it. You definitely asked a great question and I am curious what others have to say.