All the elements of the marketing mix are important, and it is equally important to make sure that there is a balance when focusing on marketing a product. It is pointless having a wonderful product, correctly priced and located in wonderful locations for sale, if there is no promotion to advertise the product. If this were the case, then not many people would be aware that the product even existed.
Similarly, the product could be marvelously marketed, at the correct price, and be a product that would be popular with the public, but if the placement of the product meant that nobody could find it when they went looking for it, the other three elements would have been performed in vain.
It is vital that all the elements interact with each other, as they all depend on each other. The influence one element has on the others mean that a balance of the marketing mix is vital to the success of the product.