I would suggest that rather than appeal to our subconscious, advertising is directed at our belief systems which are very much a conscious activity. In fact, the research suggests that subliminal advertising is not all that successful in changing attitudes, opinions or behaviour.
You suggest that most people are not in touch with their subconscious. By definition, none of us are! The moment we are “in touch” with our subconscious, the thought is conscious.
I agree that advertsing is directed at our emotions. This, however, is insufficient in creating the impetus for behaviour. As Sam Harris points out in his book, action is preceded by belief. Ads are successful because they speak to a commonly held set of beliefs.
I would suggest that Sam has been somewhat unkind to Noam Chomsky in his book, but perhaps one of the best discourses on the power of advertising can be found in Edwards and Chomsky’s book “Manufacturing Consent”. The argument here is that the media has been successful in selling a belief system that North Americans are only too willing to embrace.
Ever day as we go about our everyday lives we are totally bombarded with an endless parade of messages awakening us to our innermost desires. Accepting our culture as the enlightened one in every facet is the same as being a fundamentalist of the commercial-industrial-corporate-mass media-entertainment complex that directs our energy towards fruitless and faulty solutions for contentment and happiness.