As Jqan already pointed out, closing is a temporary state, and any question which is closed can later be re-opened. Furthermore, gaming follows a policy of close first, ask questions later. There are a number of reasons for this, but the main ones are:
Users that abandon their questions: A lot of users won't bother improving their question, and will vanish from the site shortly after posting it never to return. In situations like this we prefer to close first so that the question gets closed. If we held off on closing it for some arbitrary amount of time it's likely the question would never get closed at all. Whereas if we close it right away this won't be a problem.
It's easier to improve a question when it's closed: When a question is closed users can't post answers to it. Due to this it's a lot easier to improve a question when it's closed, that way no one posts answers that won't be valid once the question is improved (and will thus require us to clean them up).
Re-Opening a Question is Easy: By design re-opening a question is very easy on Stack Exchange. Due to this there's really no drawback to closing a question and then re-opening if it gets improved. The only drawback would be questions being forgotten by 3k+ users, and never being re-opened, but this is a rare situation. In the vast majority of situations if a user improves their question after it being closed they'll ping one or more of the users who closed the question, who will in turn bring the improved question to the attention of other 3k+ users to ensure it gets re-opened. A users can also flag the question to be re-opened, which will also bring it to the other of 10k+ users and mods.