|Which is one of the reasons why I said its the general trend. Maybe even that statement was to strong.|
All else being equal more traffic will tend to cause more revenue. Directly when the payment is for each time its shown. Indirectly when its number of clicks (more people viewing odds are more people click), and indirectly when its a flat fee per month (you can show higher traffic you can negotiate for a higher per month fee).
But "All else being equal" isn't a safe assumption as your example shows.