I've also thought of this before, except slightly different. Throughout the day, most of the time you don't really have control/awareness of your thoughts. However, if you happen to think about your thoughts, you will control your thoughts and have awareness over them. So, if you can constantly control your thoughts, you will be able to become aware of you surroundings in real life and the dream world. It's a similar concept to yours.

The only thing I disagree with is that I don't believe natural lucid dreamers are constantly aware of their surroundings. I think that they just "know" their dream is a dream, because of a distinct difference from reality or a change in perception.

Good thread, though.