I’m no marketer, nor have I studied any related field too much, but I’ve heard that it’s known to take about six encounters with an ad (or some similar mechanism) before a consumer will further engage with whatever’s being offered.

There are several stages between a consumer who knows nothing about a product and a paying customer. At first, it’s just about making you aware of their offer, so you’ll give them more attention down the line for them to make the sale.

In other words, marketers don’t expect wholly unaware consumers to become customers after viewing one basic ad.