I won't always be this way
When the things that make me weak and strange get engineered away
It's gonna be the future soon
Never seen it quite so clear
When my heart is breaking, I can close my eyes
It's already here
- Jonathan Coulton, "The Future Soon"
Many sf writers have no sense of scale - I should know, I am one. It's always an uphill battle to keep from surrendering to my base instincts and conjuring up a World of the Future that's more like the World of Next Week with a lot more shiny new technological toys. It happens again and again - most frequently in televised science fiction - and it's frustrating as hell. Why? For me, at least, it throws my willing suspension of disbelief right out the window.
Why? It's simple. Things take time to happen. Revolutionary advancements in technology or society require the passage of time to filter out of the laboratories and the subcultures into the wider world. Changes require that vested interests be brought on board or pushed out of the way. Things must be planned out, designed, and built. When a creator doesn't have an appreciation for the time necessary for things to build up inertia, whether they're space colonization programs or genetic engineering technologies, the seams of the world they've built groan and hang apart, like a brick wall made with model glue instead of mortar.
To put it simply, too many writers are too damn optimistic about the pace of events in the immediate future. Outside of a few very specific fields, such as computation, things just don't change that fast. It may take a few minutes to conceive of an idea, but to realize that idea might take longer than a lifetime - depending on what it is. Space colonization tends to attract this a lot. I found the series Planetes believable in most respects - pretty much everything but the existence of a civilian population in excess of 100,000 in Luna in 2075. I can't really see that, not unless people learn how to eat He3.
Take, for example, seaQuest DSV. If you're not familiar with it, it was a sea opera television series broadcast from 1993 to 1996 that followed the crew of the submarine seaQuest as they explored strange new ocean trenches and struggled to keep the peace beneath Earth's seas. For its third and final series it was rebranded seaQuest 2032, with Michael Ironside and a seriously rocking intro.
seaQuest itself - both of them, actually, as the first submarine was destroyed at the end of the first season - was likewise a pretty rocking submarine. More than a thousand feet long, it was powered by fusion reactors, armed with lasers and plasma torpedoes, and equipped with a genetically engineered skin that let it stand up against deep undersea pressures. Suitably futuristic, right?
Remember, though, things take time to design and build. The first episode of seaQuest DSV begins in 2017, a mere eight years from the present day. seaQuest would already have to be well under construction for that schedule to be met, but it doesn't even matter. The subsidiary technologies - its fusion reactors, its weaponized lasers, its genetically-engineered outer hull - don't exist.
For purposes of comparison, look at the United States Navy's next big project, the Gerald R. Ford class supercarrier program. It was first funded, as "CVN-21," in Fiscal Year 2001. Construction didn't start until 2007, and it's not expected to be finished until 2015. This is a design that's based on tried-and-tested concepts that have been proven for decades, an iterative improvement upon what exists.
Granted, from the perspective of 1996, a show centered around the exploits of an advanced submarine in a world of widespread undersea colonization, set in 2032, could have been plausible had everything had gone right. The fact of the matter is that things just don't progress at that kind of breakneck pace. Ideas are cheap, implementation is expensive. Too many writers forget that part.
The same problem exists in John Birmingham's Axis of Time series, first published in 2004, though to a lesser degree. His Multinational Fleet, translocated from 2021 to 1942 by an experimental wormhole generator, is centered around a fusion-powered supercarrier (USS Hillary Clinton - named after "the most uncompromising wartime president in the history of the United States," naturally) and composed of ships equipped with at least combat-capable artificial intelligences. Otherwise, it's not nearly as stuffed with superscience, to its credit.
Me, I'm trying to be careful - I'm trying to give myself more time. Sure, my stories have high technology implicit; "The Platinum Desolation" is set on a Luna with at least thirty years of colonization on it, and "You Source of Tears" involves a crewed expedition to a comet. Both of these stories, however, take place in 2078. Personally, I think that's enough breathing room for me to not look incredibly optimistic.
Besides, odds are I'll be dead before I have a chance to be proven wrong on that count. 2078 is a long way away.