I have heard a lot of people say and believe that "if your product or service is good, it would sell itself". That's not entirely true.
I believe such scenarios only happen when this product is the only one in its class facing no competition and with or without marketing the product could still sell as consumers have no choice but to buy it!
Other possibilities is if its the only alternative to a popular product and the popular product just losses its quality or maybe company closes down such a product would win the market without advertising no doubt.
No matter how good your product/services are, if people don't know about it or are not willing to patronize you, then you will have no customers or clients.
Sad reality is that its not always the best product that makes the most sells out there, but kind of like the most advertised will have the most numbers as they have won on the marketing Side of business and this influences consumers on what product to go with when they are out shopping!
I know people will argue and point out a few companies that don't advertise their products, yet they're successful
For products that make sales based on this kind of concept means they have been in business for a very long time and their clients are of a special clientele which isn't meant to reach everyone ...this is were you find car brands such as Porsche can't compete with companies such as Toyota as they have special client and they don't need to advertise either.