Stephenson makes the case reiterated so often among today's cultural and scientific elites: we aren't focused on making manifest the promises of the future (at least the kind of utopian, high-concept future of the olden days). Stephenson lays part of the blame on IT as a siphon for America's capacity to innovate (a vortex to which Yours Truly fell prey) as well as those in the culture responsible for dreaming up the next great thing.
But, America's great popularizer of science Neil deGrasse Tyson, summarizes it so much more eloquently here:
I'm unsure if Stephenson's dream of the 20 kilometer tall building, truly a Ziggurat, is interesting, and it's one grounded in pragmatism. I'll resist the obligatory literary comparison between Stephenson's building and the Tower of Babel; I am skeptical of the moral conclusions divined from mythologies written by anonymous, bronze-age barbarians. But I digress, we have the technology.... But, both Stephenson and Tyson aren't just kicking the can down the road to the next generation of kids with agile, unbroken spirits; they are trying to lay down the cobblestones to help them find the future. This author does believe they are correct when asserting that building a dream, albeit a fictional one, is the likely first step.
As a film school graduate (and ardent SciFi fan), I am saddened that my young nephews' exposure to science fiction has been reduced to Michael Bay's infinitely-stupifying forays in the banal spectacle and George Lucas' uninspired retelling of the story of Jesus of Nazareth (with light sabers). Hollywood cares little for stories with new ideas, and even less for subversive or un-focus-grouped tangents. If we rest the responsibility for dream-making entirely in the hands of Hollywood, those dreams will likely be as hollow and forgettable as any creative work made exclusively for profit and by a committee well-fed plutocrats.