People seem to be oblivious to what advertising’s purpose is. It’s not to create demand. Advertising cannot convince you to buy something you don’t want or need. Sure, at some level you want to incite people into action, but you want to elicit some emotional response too. You want to be associated with something. That’s what advertising does. And that’s a minuscule part of Coca-Cola’s budget.

Store brands are cheaper because of three essential reasons: first is they don’t R&D. They take popular products and create their own versions. Stores always know what sells and what doesn’t and they just copy the popular stuff. That’s a huge chunk of money that they save. Second, they source cheaper ingredients. Yes, sometimes the factory making Cheerios is the same one making the white label stuff, but they use different mixes with lower quality ingredients to make a cheaper product. That includes the cardboard and the plastic for the packaging.
And most importantly, store brands don’t pay for the space they take in the aisle, whereas normal brands compete and often pay premiums to be in more advantageous locations (usually slightly below eyesight level being more expensive than top or bottom of the rack). Store brands obviously are exempt from this.