[Illniyar]

"• Google earns more ad revenue as users stick around on Google longer"

This one is actually reverse. Google search doesn't net google any money if people don't actually click the link, since ad revenue for google search is Per Click, not per view (per mille).

The incentives for them are actually reversed - increasing the amount of clicks into external websites, specifically advertised links, increases their revenue. (which is why there are so many advertised links on a search page)