The discussion I opened today was not about the reasons or causes for off topic posts. Re-evaluating which topics the community feels should be on or off topic is the specific point of that post. Allowing answers that are not addressing that question takes away from the whole purpose for opening that question for discussion.
Suggesting reasons for why we get off topic posts or how we can reduce off topic posts does not address that question in any way. That is an entirely different question and if you would like to have that discussion, you are free to start it yourself or suggest that someone start such a discussion.
While your suggestion may be entirely valid and a perfectly good discussion to have, it does not fit where you posted it.