That's not entirely it. Some people just won't say something unless put in a setting where they are explicity asked for it. I've had meetings where I ask for a status, and someone says they are stuck on X, and they've been stuck on X for two days.
And I'll ask why they didn't just ask for help. They weren't comfortable asking for help. They were only ok stating the problem when asked specifically for status.
So it also creates that environment were some people are more likely to share.