We will never extend it out that long, but will act as a medium if you do want to edit something in that keeps the posts in context, at least when it comes to discussions. This is because editing (or deleting) posts in threads can harm the flow of conversation that took place over those days and make it read out of context to just be plain jibberish to future readers.
The marketplace is another topic. We might extend it out to a week or so in order to edit the first post to always include new information, etc.
Thanks for the suggestion though!