The Importance of Advertising
Read the following example of the importance of advertising and think about the damage that NOT advertising can do to your business:
Advertising and Advertisements: If Coca-Cola stopped advertising while keeping the product in full supply, would people eventually stop drinking it?
The answer to your question is no, but...(read on to find out why it would be incredibly devastating for Coke still)
Advertising in the fast moving consumer goods area (FMCG), especially in the beverages market, is all about Mind Share and brand perception. To become and stay the dominant global brand, you have to be ubiquitously well-known. Of course, you also maneuver the consumer's perception of your brand with advertising, but I'll leave that aside for a second. The highest goal achievable when it comes to Mind Share is to achieve a state of conditioning (or preconditioning) of your potential customers. A level below that, you want to definitely be at least in their relevant set. Let me explain:
Think candy bars. There's a relatively high chance that you have two to three or even up to five in mind immediately, and that none of them ranks miles above the others in your head. This is your relevant set. Everytime you feel the desire to have a candy bar, you will take these two to five into consideration. So, sometimes you might choose a Snickers bar, sometimes a Butterfinger might fit you more, but you will hardly leave your relevant set.
For an FMCG company, achieving the goal of being in the relevant set of their potential customers is already a huge success. Because this process is highly driven by Mind Share created through awareness created through exposure created through advertising pressure, your advertising budget plays a major role in achieving this goal.
If you one-up your advertising and influence carefully how your brand is perceived, you might be able to condition or precondition your customers. Think cola. Oops, I bet you didn't think cola. I bet you thought Coke. And when you think about the color you had in mind, certain shapes of text or a bottle, Coke just might have cought you there, too. Advertisers call this habitualization. Picking Coke has become less of a choice (which it would be if it were only part of your relevant set) but a reflex. Now, this goal cannot be achieved through your product just standing around in stores. That is a major advertisement undertaking. You have to apply constant advertising pressure to make sure that no other brand trumps you in Mind Share. Because if so, that other brand will be the first coming up when the desire for a can of cold cola pops up, or might at least shift the situation in the consumer's head from a habitualized one to one where the consumer has a relevant set. This is called de-habitualization, and for companies like Coca Cola it spells d-a-n-g-e-r.
So, in short terms: No, people wouldn't stop drinking Coke if Coca Cola ceased advertising it. The Coke brand would face subtle extinction by becoming more and more irrelevant, though.