[hungryfoolish]

>The industry is a fundamental conflict of interest, designed to convince people in most cases to buy things that they may not need

Thats a bold assumption. If I have a business then I will advertise my product in the hope that people will see it and make a decision by themselves on if they need or want it, and make an informed choice to buy it.

Besides, its not about needs, but also about wants. Humans are driven by not just strict needs, but also aspirational desires, ambitions and tastes. For e.g, nowdays you don't really need a wrist watch anymore since you can tell the time from your mobile phone which most people already have, still the demand for such watches is there because it seems to fulfill some other desire that there is no longer any strict 'need' for. There are various ways you can make such watches (different price points, aesthetics, quality of materials, after sales service etc) which also appeals to different sets of humans. Ads help in getting the word out on your brand of your wrist watch in the hopes that some people out there will find it appealing enough to buy it.