A bad team isn't going to be made good because of lunch. But I think the point of the article is that it can make a good team (full of very skilled people who are unenthused about their work experience) into a great time (full of very skilled people who enjoy spending time with each other much more). And sure, a group that constantly bickers isn't going to instantly transform because of spending time together, but it could build enough of a community to bring together groups that get along fine but aren't that friendly.