I think that you make a very good point. I don't know that predicting the future is futile, so much, because some of the things that, in the past, were in the realm of Science Fiction that have become commonplace, like handheld computers; being able to talk in real time, including video, with people from all over the world; electronic repositories of knowledge that can be accessed at any time by (almost) anybody; robots that perform functions that used to take several humans, in a fraction of the time, with fewer errors, etc. Heck, it wasn't that long ago that the thought of man landing on the moon or being able to fly around the world were considered pure fantasy.Obviously predicting the future is futile. It's likely you'll get just as much right as wrong. But to be able to inspire a young kid about the possibilities that the future has is what EPCOT Center was about, and there's no reason it couldn't be that again, in a more modern context, while still appealing to the masses.
You hit on what I think is the most important aspect of what EPCOT Center caused: Inspiration. By focusing on ideas, it was able to implant the desire in young and old alike to say, "What if?" We were shown the progress of man from prehistoric times and made to feel proud of mankind's accomplishments. It wasn't all whitewashed, either. We were presented with the difficulties that face us today, but shown the possibilities of things we could explore to overcome the obstacles in our path. We were told, in pretty much all of the original pavilions, that man's struggle to progress is not new, but has always led to achievement because of mankind's intelligence and tenacity. Both Future World and World Showcase were infused with hope for a better today and tomorrow. Whereas the Magic Kingdom is all about escapism, EPCOT Center was all about the wonders of reality.