Amazon makes money whenever you buy their content. Google not so much.
When you have a strong platform player that have decisive power over how they locate information — in the case of Apple, (1) control over the default search engine in Mobile Safari, (2) control over what web browsers are approved for their App store (3) has their own maps app backed by their own services and partners, which doesn't include Google (4) demonstrated capability and intent to build alternate ways to access information such as Siri (5) demonstrated animosity — I'd say Google doesn't feel like they win if you buy an iPad.
So correction, it should be "Google makes money when you use their services".