Perhaps, but at least we have some evidence for it. Archaeological remains, documents, images etc. Our precise interpretation may vary as new evidence emerges, new theories become popular and so on, but we have a pretty firm idea of the basics. Depicting the future, however, especially the distant future, is far more difficult and therefore dates far more easily. Technology is advancing at a dramatic rate, for example. At one time it was foretold that man would travel to the moon thanks to an enormous gun. Just as fashions change in the way we interpret history, so it is with the future. At one stage the future was bright and shiny, sleek and sterile white. Then it was bleak and grimy and functional. With the success of the new Star Trek films the pendulum is perhaps starting to swing back to shininess. On the other hand the new Star Wars films (futuristic, if technically set in the past - albeit in an alien galaxy) will bring back the brand of realism that was always the franchise's trademark. (The elaborate and complex 'Expanded Universe' of the Star Wars franchise could itself be likened to the evolution of interpreted history, but that perhaps is for another thread).