Why do companies whose products are mainstays...Coke, Pepsi, Lay's etc, continue to advertise?

That's how they stay mainstay.

Let's face it, they are not always the best product in their category. I can remember when our areas' favorite brand of potato chips was NOT Lay's. It was a local brand, but Lay's came in with better profit margins and discount deals to the consumer. They 'forced' their way into our homes. ( I still buy the local brand) 

Possibly because such products are not available through hunting or gathering....?---and must rely on an artificial demand created in the marketplace.

With all the sugar ,chemicals,trans fats and others crap in them ,they need to stop people buying others far healthier chemical and G.M.free options...  

 Competition. 

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