When I worked in D.C., our company's 80-year-old billionaire owner would come in every now and then. He had a personal assistant/driver that went around everywhere with him--this guy was also getting up there in age--probably in his 60s. He is the one who told this story to me:

They were both walking through the lobby and there was a nickel on the floor. The driver walked past it and our billionaire owner bent down, picked it up, and pocketed it. He chided the driver and said "you never pass by free money. Ever."

While you are right that it wasn't worth his time to reach down for the nickel, that was his mindset. You don't become a billionaire by not cutting costs or by passing up money-making opportunities when they arise.