The problem with the "past" link is that it appears regardless, so it's barely better than copying the link and pasting it in the search box. The advantage of these posts is the lack of friction, they're just there.
I think dang himself clicks on 'past' and then refers those links here.
What would be great is a (sticky) comment for all past discussions sorted by year.
That’s pretty much what the “past” link gives you. I like the human touch of someone consciously deciding whether there’s value in highlighting previous posts.