I was surprised by this answer – but it is a community-specific or site-specific decision, i.e. what kinds of questions they want to allow or prevent for what range of subject matter.
Perhaps your question is mostly about this …
… i.e. evolution or change in a site’s policy, or the balance of users’ interpretation of its policy.
One possibility, I don’t whether this might be a factor – when the number of users grows, does it become easier (and perhaps too easy) to find any 5 users who will vote to close a question?