You’ve fallen into the fallacy of equating availability of advertisement to availability of knowledge. Knowledge is supposed to be a direct result of some observation of reality, advertising is usually a created and modified reality designed by someone (who is using their knowledge of the psychology behind it funnily enough) which displays the product or service as a requirement for improvement of the person being advertised too’s life. The goal of advertising is to sell, the result of knowledge is to understand. Two very different things.