Ok - so the saying has been used a bit too much. But it still works. Thinking outside the box means putting things in a different context. As an example, sometimes ordinary sayings can become catchy slogans if put in a new context or expressed in a new way.

Nike's slogan, "Just do it" is a classic example. (An imperative slogan - see types of slogans). They didn't create the slogan, it was a common saying. Many moms and many bosses had been saying it for years. But Nike put it in a new context. What they are saying is that most sports aren't complicated and don't require a lot of special equipment, just a comfortable pair of shoes and a ball. The key thing isn't the equipment, it's doing it.

Applying a slogan that already had a meaning to people made the slogan catchy. It sticks.