Most humans aren't good at imagining things that don't exist yet. Our visions of the future tend to be either wildly inaccurate, or boringly prosaic. Whether or not Henry Ford actually said it, most people probably would have asked for faster horses, because we're not capable of conceiving of the next great technological leap forward until we’ve already seen it.
A new technology needs to be close enough to an existing one in order for people to be able to get their heads around it. If it's genuinely innovative, radically different from anything that people have seen before, it probably won't be successful. If we can relate it to something familiar, that gives us a foothold to be able to understand it. We see the same phenomenon everywhere. With new businesses, if you can describe your startup as "like Uber, but for dogs", then people have a way to get their heads around it. Cinemas are full of sequels and adaptations, and there's a reason why so many music reviews follow the format "sounds like X meets Y" - people need a reference point. We crave the excitement of novelty, but want the comfort of familiarity. In other words, we fear change.
In order to reach point Z, we can't just jump straight from A. Sometimes new technologies really are ahead of their time, in the sense that the world isn’t ready to accept them yet. We need waypoints along the journey - incremental change is easier for people to cope with. We probably couldn't have gone from cine films to Netflix without being gradually led down a path via VHS (and Betamax), DVD, Blu-ray, hard disc recorders and YouTube. Similarly, we can look back at the Walkman, MiniDisc and iPod as gateway drugs to Spotify.
Some of these technologies stuck around for a few years, while others were little more than stepping stones on our journey, but we haven't reached the end of evolution, either biologically or technologically. The things we see as state of the art now will, sooner or later, become antiquated. Later generations will view our current wonders as transitional technologies, quaint relics of progress, or perhaps at least planned obsolescence.
Nothing is permanent, no matter how much it feels like it at the time. History is full of examples of empires that would have seemed indestructible only a short while before they crumbled. Google and Facebook may currently have dominant, seemingly unassailable positions in the market, but it's not so long ago that they were the scrappy underdogs, and things can change again.
What is the shape of things to come? If I knew that, I’d be rich, but I’ll venture one small prediction. If you were designing autonomous vehicles from scratch, you probably wouldn't start by taking a car and putting a robot driver in it. The future is in another direction, but self-driving cars are all that our feeble minds can cope with at the moment - they're the transitional technology that we need in order to accept the idea. Once we’ve taken that difficult first step down the road, we'll be able to continue our journey. This is partly why the iterative nature of lean and agile is so important - we don't know what we want until we see it (or something we realise we don’t want). A first draft is a useful strawman to build upon, something that exists so that we don't need to imagine it.