I don't have any reference or precedent to back this answer up either, but I wanted to suggest the opposite approach (somewhat in line with @DarkCygnus in their comment on your answer).
To be clear: the hypothetical scenario is: a (new) user posts a question that isn't clear/is poorly structured/otherwise is hard to answer. People comment and downvote on it. The user comes back, and posts a second question which is essentially asking the same thing, but is better worded/structured and meets general SE criteria.
The problem with keeping the first question and deleting the second one is, you end up with a lot of baggage - even if the actual text of the first question can be revised (by copy-pasting from the second post or direct editing) it's hard to overcome not only the negative votes, but also the comments, which now make no sense after the substantial edits.
If the second post is substantially better in terms of being a clearly worded and on-topic question, keeping it open (and closing the first) avoids the issue of having to clean up the noise and overcome the negative votes. In other words, it gives the user a better chance at actually getting positive attention and good answers.
If the desire remains to keep the edit history from the first post, you could always link to it in a comment on the second post.