go the way of the dinosaur(s)

To become extinct, obsolete, old-fashioned, or no longer in common use. If we don't get climate change under control, we're going to see a number of animal species go the way of the dinosaurs. With the sudden ubiquity of smartphones, it seemed like wristwatches might be going the way of the dinosaur. Thankfully, such ignorant views about interracial relationships have largely gone the way of the dinosaurs.