It’s surprising since it seems directly from reuters and not one of the PR wires. They’re so confident about it!
Nearly every news outlet and publication does this and not just Reuters. It's very pervasive and it's not new. Sometimes, it's official, other times it's just a PR agency with a story and a reporter who needs one. I'm sure there's a lot of quid pro quo, but there's little that I've seen written on the subject beyond Paul Graham's essay.
Let's not blame the journalists here, if GM was proud of how many they sold out of, they would say so. A journalist asking them isn't going to change that.
The job of a journalist is to ask questions and not be satisfied with just repeating what a corporation wants them to say. Just repeating a company's PR is the job of an advertiser.