Obviously, there is a bit of strangeness here: a 1950s computer, with all its tubes, light bulbs and Billions of Buttons, looks vastly more technological and complicated than the plain MacBook, even though the MacBook may have literally millions of times more processing power than the old 1950s computer. This fallacy generally overlooks that one hallmark of advancing technology is the "comfort factor" we design in: something new and marvelous may well look all techno-, with exposed wires and flashing lights, but as technology advances even farther, this techno-miracle will be refined until it can be given a form factor that doesn't stick out like a sore thumb. After all, it takes much more technological innovation to create the minimalist wallet-sized cellphones of today than to build a World War II army field phone. In addition, there is the factor of Moore's Law and similar concepts for memory storage, circuit size, and energy efficiency: as integrated circuits become increasingly compact, electronics tend to shrink. Compare a nearly room-sized computer to the smaller, simpler Apple II, then compare that to today's smart phones with orders of magnitude more processing power
Design aesthetics also change over time, totally independent of technology. In the 1950s, people thought that flares and tail fins looked futuristic. But we have just reached the impossibly far-off AD 2019, and very few things have tail fins, aside from actual fish, airplanes, and the Batmobile.note Ironically, things like flares and tail fins now look decidedly retro: recent models of the Ford Thunderbird have fins to keep the vintage '50s feelnote .
In general, as the "future" becomes the present the miracles and advances tend to look not-quite so flashy as people in the past imagined them. Even if they change our lives enormously, they tend to do it in such a subtle way that you might not even notice by looking. The newest Boeing 747's look nearly identical to ones built in the 1970s but they're far more advanced inside. Some modern family cars are quicker than vintage sports cars, but they don't look as fast. A 2009 Dodge Challenger features all sorts of electronic pizazz such as cruise control, traction controls, computer-controlled engine, side airbags, GPS, voice recognition and whatnot, but outside it looks like a modernized 1970 Challenger. Your modern office building using modern building techniques might not need flying buttresses to hold it up, and it may indeed look a little different from the office buildings of a hundred years ago (it might even be a modern construction built behind a 19th century façade), but it's not an organic-looking chrome spire seven miles tall with pneumatic tubes instead of elevators. We could probably build them that way, but we don't, because that's neither practical nor what our design aesthetics call for... well, outside of Dubai, anyway.
In rare cases, some design choices do age well, which can make them appear more modern now than when they were first produced. Stanley Kubrick's adaptation of 2001: A Space Odyssey is an excellent example: in utilizing the minimalistic Ascetic Aesthetic design fad of the 1960's as the primary design aesthetic, it inadvertently matches today's vision that Everything Is An I Pod In The Future in numerous instances, such as Hal's interfaces being a simple red lens and speaker on a plain surface, rather than a complex panel covered in buttons, switches, and blinking lights, and his core is oddly similar to modern plug-in server rack layouts. Likewise, the original Star Trek's sets are generally much sleeker and more minimalistic than those of its prequel series Star Trek: Enterprise, but at the time Enterprise was on, viewers complained that the prequel series looked more advanced, because minimalism was out of fashion at the time.
There's a recursive element at work here, too. It's overwhelmingly likely that Steve Jobs saw 2001: A Space Odyssey at some point, and he may have been influenced by it. Flip phones are passé now, but when they debuted, it was no secret that they were imitating the communicators on Star Trek: The Original Series. And modern computer screen layouts and even alert sounds are suspiciously like the ones on Star Trek: The Next Generation. As the saying goes, art imitates life, and life imitates art. Our predictions of the future are often wrong, but conversely, they also often end up being self-fulfilling prophecies by giving us an expectation of what an appealing future is supposed to be like note — or, in this trope's case, look like and designers often aim for that model, consciously or not. After all, they know that that's what looks futuristic to consumers.