Not only was it truly mind-blowing at the time, but in retrospect, so much of modern computing was invented for that first iPhone phone and revealed to the world for the first time in that hour. Just watch the software demos: most modern UI mechanics and behaviors, large and small, began that day.
With ten years of perspective, perhaps the most remarkable thing about the iPhone is the fact that, for all its retrospective imperfections, the original model was in fact so conceptually perfect, right out of the gate. Automobiles had to evolve for almost 40 years until they settled into the standard configuration we are familiar with today. On their first attempt, the team at Apple managed to stumble upon the perfect form factor, the perfect incarnation of the modern smartphone. Smartphones had existed for several years previous to the iPhone, but the standard form of the smartphone as we know it today — physical keyboard-less, a single slab of screen, a “black mirror” that is both a reflection of, and a conduit for, all of our hopes and desires — they nailed it on the first try. And that’s quite remarkable. Whatever you may think about the subsequent lawsuits and charges of copycat-ing, there’s a very good reason why everyone in the industry moved toward the paradigm the iPhone pioneered.
Plenty of commentators are expressing similar sentiments today. The iPhone really is the bridge into the post-PC world.