The confusion is that Google has two businesses that are integrated. They have products that are advertising supported and they have an advertising platform available to others.
Google could kill their open AdSense product completely and still make billions dollars selling ads on their products.
Google is a ad monopoly, they own the method of delivery, the ads, the monetary distribution and the placement.
That's an advantage that no other company can claim, and basically means that you can't compare them in this context at all.