I believe that ALL of the basic functionality of the site is part of an available template. Dirk has said that nothing is cast in concrete yet so perhaps the 5 minute limit is a variable. Usually there is a time limit plus the condition that no further replies have been made to your post.
I like the way several forums I‘m on do it. You have 10 minutes to edit your message, as long as no one has replied quoting it. After that, again if no one has quoted it, you can edit your message but a note is added to it that it has been edited.
I think that gives enough time and opportunity to correct typos or other minor errors.
We can continue to complain and repeat for the next 10 years, that dpreview had this or that feature, or we face reality and try to make the best out of the existing features and possibilities
It is like with cameras. If a specific feature on your camera is not exactly at the spot where you would love to have it, you do not stop using the camera, do you? You can still make great photos with it.