I have to wonder, though, why it matters to anyone here, or elsewhere, whether I take three weeks to world-build, or five years, before I start writing?
Unless I want to read your finished story it doesn't matter one bit to me how much time you spend building the setting for it. The original thread about world-building was intended to point out the potential negative consequences of spending too much time worrying about the world and not enough on the setting. The discussion might have gone a slightly different way, but at the moment that's how I understand it.
The reason for highlighting these potential issues and creating a discussion about them was to make aspiring authors here on the site aware of them.
As ThinkerX pointed out, the issue with giving the world too much space in the story isn't all that uncommon here on the forums. It's something that happens, especially to new(/young?) and inexperienced writers. So creating a discussion around it may serve to highlight the issue and make someone think a little extra. Maybe they'll decide that the complete history of the entire world isn't relevant to the reader of a story about just one of it's inhabitants.
I don't think anyone tries to tell anyone how much time they should spend on world building. I think the message is to not let the world get in the way of the story - if completing the story is the goal.