Google News is worse than average for sticky traffic.
Hitwise has run the numbers on traffic that returns to media sites according to referral site. Facebook is far and away the top returning traffic referrer. Google News doesn't come close.
Perhaps the newspaper industry's frustration with Google News is misguided. Ok, we already know it is. Google is simply indexing sites (with the exception of licensed content deals) - and users click to go to the site. Google sends traffic. But the quality isn't as high as other sites.
Also a factor is that so many Google News readers scan headlines, whereas shared news stories in Facebook are mixed in with status updates, etc. Perhaps your network is more likely to share news stories/sources you're interested in.
Google seems to know that. They introduced customizable news sections recently. But the interface can still be choppy and the stories redundant or irrelevant.
By the way, Google.com wasn't included because it performs worse than Google News!