Ads aren't about making you buy the product immediately. The goal is to make you associate the product category with the product. For example, when you think of washing detergent, which brand do you think of? Of course you think of Tide. Why? Because their advertising works. Which brand makes burgers? McDonald's. What's a refreshing fizzy drink? Coke. This comment is also an advertisement for Tide, McDonald's and Coke because every single time you see them it strengthens your recognition.