Well, unless someone is specifically looking in the GSRA forum, they will not be drawn to it unless they are looking the "Newest" or the "Active" listings. I usually open a new posting when it appears in the "Newest". 24 hours later it drops off the list. So, really, if no one is responding or posting after 3 days, anyone without pertinent information would not have much to add anyway.
Still, I've seen other threads remain open with no comments for a long time afterward. Some never close. I guess it all depends upon the moderator. I'm sure he's following guidelines too.