I think the takeaway is simple.
If you have a legit shot at the playoffs, you should go for it (at least somewhat), and not sit pat. You don't need to blow up the future. There are players to add that were once good, and might get hot/good again. You never know if you'll be in that position again (at least if you are most teams), so don't just sit still or give up. Try to get better, even if only at the margins. Atlanta got lucky, but that is largely the story of the post season, given the short nature of playoff series.