Science fiction and retrofuturist visions alike are rooted in a deep pragmatism. Whether it's spheroid, rolling homes, a giant dam to melt the Arctic, or even a dystopian wasteland, future minded folks are driven by the idea that a new development, a new innovation somewhere on the horizon will solve our problems. But what problem, exactly, is solved by putting women in tubes?
That question (one which I'd never thought I'd ask) is raised by the appropriately named blog Sci-Fi Women in Tubes, which has aggregated the absolutely absurd amount of sci-fi images and artwork that involves women being trapped in glass cases, plastic orbs, weird sleeping chambers—whatever container you can imagine, there's been a woman put inside in some old sci-fi pulp.
It's a positively fascinating phenomenon when you're faced with how widespread it was (is?). As you might expect, the majority seem to be of the Sleeping Beauty persuasion: a woman—perhaps in distress, perhaps asleep, perhaps gesturing lustily—is in need of saving from a male protagonist. (Others are a little more trippy.)
So, yeah, there's a problem to be solved. The damsel in distress is the oldest trope around. But a woman being trapped in a tube isn't a problem in the sci-fi sense, some over-arching threat to humanity as a whole. As far as I can tell, most of the women appear to have ended up in tubes because some evil jackass put them there. Why? Why is this so persistent?
Does it have to do with some root fear of sci-fi aficionados with regards to aging? Just like my sealed Star Wars figurines, I must keep all my women in vacuum containers to keep them mint. (Naturally, that's what drove Comic Book Guy to turn evil.) Preserving women like vegetables in the crisper could be a strange offshoot of the futurist obsession with the technological fountain of youth, but I'm not convinced that's enough for it to become such a pervasive meme in the genre.
In tech-heavy sci-fi at large, women are often treated as perfect, albeit unreachable, objects. Whether the beautiful replicant Rachael in Blade Runner, or the mostly-soulless Major Motoko Kusanagi in Ghost in the Shell, sci-fi women in the cyberpunk era were often treated as being impossible to reach, regardless of whether or not they were in charge.
Perhaps that's an evolution of the themes spun out of the era before that, the retrofuture, in which women were placed in tubes where they were literally out of reach. Is that a fantasy derived from real life (and real awkward) masculine lust? If my hero is struggling to get the girl, who's sealed in a dastardly tube, then why should I stress about not winning over the girl at the deli counter? You know, so-called nerd shit?
Ah, maybe I shouldn't be reading into it that far. Saving women has been the premier job of literary white knights since the beginning of time. It's goofball and mysognistic and kinda sad when you get down to it. To think that the only way you'll win the girl, get her to love you, is to concoct some elaborate fantasy where she's stolen away by a lizard king and trapped in a castle, upon which you then save her and she swoons, is a bummer at heart, because chatting and having a goof without all the kidnapping and whatnot is generally a better course of action.
Damsels in distress still pop up left and right, because how else will you know you've really won the girl? So yeah, Rapunzel was hot shit for children's stories, and Princess Peach just had to be saved from Bowser's castle. I suppose that it's not all about sinister worldwide literature conspiracies to trap women in Lexan, and we can probably toss the pop-psychology.
So to answer the original question, being trapped in tubes isn't a futurist problem to engineer our way out of. The only problem putting women in tubes is solving is that of authors' own lack of creativity. All these women in books are getting trapped because it's the laziest plot device in history, and as such will keep appearing, whatever the genre, because there are a boatload of lazy writers out there. But as far as I can tell, there won't be any castles in the future, probably because it's hard to integrate computers into them.
So this is how I imagine the tube thing came about: one dude (of course it was a dude) one day was staring at his brand-new writer's journal, and thought "Hey, I need a kick-ass character to save a woman, because that's popular. But how do I get her trapped in the future? There's aren't any castles in science fiction. Oh, shit!" *slaps forehead* "You know what's futuristic as hell? TUBES. Let's put some hapless beauties in tubes!"