Imagine people who are sitting in a train with all seats facing opposite to the travelling direction. The vision on the past journey is clear, but it takes more effort to see which direction the train is heading for, The driving direction however remains hidden regardless of the effort of the observer.
I believe that this version of the allegory is more appropriate in the modern world that has - contrary to Plato's time - taken on evolutionary speed. For every generation it has become possible to have a clear view on the past journey of humanity and with a twist of the head, the luck of a seat close the window and a train that keeps a moderate speed even a portion of the future journey can become visible The ultimate goal of the journey however remains hidden regardsless of the effort as the train itself is obstructing the view. Also the question on how and by whom the tracks were laid still remains a mystery.
But as far the homo sapiens within the train is concerned: Plato remains an up to date reference and a story that will keep its audience for the foreseable future.