Virtual reality sounds like paradise: we'll upload our consciousnesses, ditch our smelly meat bodies, and be beautiful, immortal rockstars in a scarcity-free wonderland, forever. But technology never quite works out the way you hope it will, and science fiction writers have already pointed out four ways virtual reality could suck.
You'd never have enough computing resources to make it work
In Rudy Rucker's novel Postsingular (available as a free download), nanomachines (called "nants") turn the world in to a virtual simulation, called "Vearth." And it turns out that Vearth is kind of a sucky copy of the "real" Earth, because it takes up too much bandwidth to create a decent version. "The water, clouds and fire were never quite right. In any case, the nants didn't always try that hard; they often settled for shortcuts as crude as representing a tree by a cookie-cutter flat polygon."
And then the Big Pig, the super-intelligence that runs the simulation, comes up with an economy, where if you pay a monthly fee, you get rendered at a higher resolution. There's only so much room to live in Vearth's highest resolution and best-simulated zones, so most people have to live in tiny apartments or in worse areas. And then a rival programmer named Gustav rises up, offering equal computational resources for all — unfortunately, those computational resources are limited at best, so Gustav's whole world looks like an old-school arcade video game.
As virtual people are having more and more virtual "children," who were never "real" humans to begin with, overcrowding becomes a serious problem and people compete for bandwidth. "Vearth could only support so many virtual agents. With the birth rate going up, the older and weaker sims were being culled out." Eventually, there are terrorists and computer viruses that wipe out tons of people. And the Big Pig realizes that people can get along without their subconscious minds, so it takes those away.
In a similar vein, Jim Munroe's classic novel Everyone In Silico (available as a free download) takes place in a near future where a corporation starts porting people to a virtual version of San Francisco, called Frisco. It's beautiful and immaculate there, but a lot of the people are just cookie-cutter copies of the same icon. One character visits a temple in Frisco:
Another monk, this one refilling the holy water, gave him an identical disapproving eyebrow. This time he didn't bother apologizing, just found a pew near the back and sat down.
You'd think that since they've bothered to make a temple for themselves, they'd make a couple of different types of monks instead of cutting and pasting....
Another cut-and-paste monk walked by, holding a small flame cupped in his hand, and Paul's ire was whipped up again. We had an infinitely varied environment on Earth, and we painted over it to draw our little stick figures....
"What do you think when you see that?" Paul said, pointing at the two monks, one at the altar and one cleaning stained glass.
"That whoever was doing skins was fucking lazy," Jeremy said, returning an eyeball back under his sunglasses. "But that's the way it is here, man. It's not just the skins," he said, spitting teeth as he said it. "It's the architecture too. And the security. That's why there's so many holes for rats like us."
Paul looked at him, expecting he'd have changed his zombie face for a rat one, but he was back to normal. "Just laziness, huh?"
"Well," Jeremy sighed. "OK," he started, wearily accepting Paul's seriousness. "It's like this. I've got a friend who does skins for environmental characters. He gets shit-all for it, and they're always on him - they want, like, 75 a day - so he can't spend time on the details. So he churns them out. He's made some wicked squidmen for an Atlantis environment, though."
It would be too predictable, with no danger or discovery
Robert J. Sawyer's paleontologist character in Calculating God learns that every intelligent species either blows itself up or decides to "transcend," uploading its consciousness into cyberspace. The idea of giving up corporeal existence doesn't appeal to him, because it would be like giving up your humanity: no more skinned knees or broken hearts. But the clincher is that it's too predictable. "Virtual reality was nothing but air guitar writ large," Sawyer writes. You could go on a simulated dig, and even discover fossils there — but they'd only be there because you wanted them to be there, and they wouldn't advance our understanding of evolution or the universe at all.
As Sawyer explains in Factoring Humanity:
The problem with virtual-reality simulations was just that: they were simulations... There was a fundamental difference between skiiing in Banff and skiing in your living room; part of the thrill was the possibility you might break a leg, part of the experience was the full bladder that couldn't be easily voided, part of the fun was the real sunburn that one got during a day on the slopes, even in the middle of winter.
It could suck if you're not middle class
Veteran editor Gardner Dozois discusses the "virtual reality" future in his "Summation" in the 1997 volume of The Year's Best Science Fiction And Fantasy:
I'm not sure that I believe in this future, although no doubt bits and pieces of it will come to pass. For one thing, it seems like a very middle-class view of the future, ignoring — as, indeed, does most science fiction — the question of what all the poor people are going to be doing while everyone is leading this Maximum Urban Cocooned existence. Are all the poor people going to have Virtual Reality cocoons too? Who's picking up the garbage? Who's sweeping the streets? Who's fixing the plumbing? It's like a future where only the Eloi are around; no Morlocks. A mistake that much science fiction makes is to assume that social change affects everyone to the same degree at the same time — which isn't the way it usually works. There are people living within fifty miles of my apartment in Philadelphia who don't have electricity or indoor plumbing; there are people living within a thousand miles or so of here, in rural Mexico, say, who are living a hand-farming subsistence not really different than the one their ancestors were living hundreds or even thousands of years back...
The point being that the present is not at a uniform level of social development, so I doubt that the future is going to be like that either. I wonder, in fact, if, in the future, we're going to see people living at a Stone Age level — or living the way most of us in the West do now, for that matter — side by side with people living such a high-tech existence, at such a level of technological sophistication, that they're nearly incomprehensible to us. But the different levels of technological sophistication will be layered throughout society, like the layers in nougat, the whole spectrum from Stone Age to Incompehensibly Advanced Singularity Folk existing side by side at the same time; it won't be all one uniform layer, Virtual Reality Cocoons all the way down.