Forever conditioner

I saw a new set of shampoo and conditioner available as a set in a store. It was lined up in a wooden box - one bottle of shampoo, and about six bottles of conditioner. You use the shampoo every time you wash your hair, and slowly use up each conditioner bottle and move on to the next. By the time you finish the last bottle of conditioner, your hair will be PERMANENTLY CONDITIONED and you will never have to condition again.

I was quite excited by this idea, but I wondered, why do they give you only one bottle of shampoo?