Has this not been submitted to HN many times before?
searchyc.com[0] yields a lot of results, so you're definitely right with your statement.
I think we have to take into account that the number of HN users has probably grown quite a lot during the last year or two, so a link that you already know because you saw it on the frontpage may be new for the one or other user. Hence, I wouldn't be surprised if we'll see more dupe links of this kind on the frontpage.
Besides, this type of link isn't necessarily a "news" story that will become outdated.