Advertising is the only way for the owners to make profit from their product. It is obvious that there must be advertising so that many people spend their money on it which, as a result, makes the product spread all around the world. But in this case, advertising the product will not affect on its successful spreading.
There are a lot of things the human-being is dependent on. We can all agree that the most important product in our lives is water. And there is a question: have you ever seen the ad for water? Of course, there are advertisements for pure and distilled water. But there are none for the water consumption itself. The reason for this is that the hydrogen dioxide is the product the people can not survive without. We use water, we drink water, we buy water because we are led by our instincts. And our human-nature tells us it is impossible for us to live without it. This is what makes us buy and consume, use the essentials. And it is not only for water.
On the other side, the advertising has huge benefits for the owner. Companies can advertise their product not only online, but it is also possible to make it in real life, face-to-face. Suppose, there is one family lives in the mountains, which is common for Asians, and they know nothing about pure water because they drink it from the nearby river. This is not healthy, first of all. But it can be prevented by the help of advertising. The company visits them and advertises their product which may persuade the family to buy it. As a result, both sides are satisfied: the company, which made goods and the family, which now has water that is safe to drink.
In summary, I cannot exactly say whether the advertising is needed or unnecessary. It again depends on the situation, people, and many other factors. But in this case companies do not need to advertise their product as people themselves try not to run out of essentials. If people need it, they will find ways to get it. And it doesn’t matter if there is the ad or not.