... Lem preferred to depict societies bogged down by excess information and technology. “Freedom of expression sometimes presents a greater threat to an idea,” he writes in his 1968 novel His Master’s Voice, “because forbidden thoughts may circulate in secret, but what can be done when an important fact is lost in a flood of impostors … ?” This observation rings eerily true today, but Lem wasn’t only trying to critique modern society. He wanted to imagine what the future might actually be like.
The reason why SF has traditionally trafficked in a cautionary view of the future is as a corrective to human hubris. I don't think having a positive, actionable vision of the future necessarily results in a positive, actionable future: you might bring to life some of the artifacts of that vision, but the vision itself is just that: a vision, not real.
Plus, once a vision leaves your hands, it's not yours anymore; it can be turned against its original conceit and wrenched out of its original context as easily as it can be deployed.
That's why SF tends to be cautionary and dystopian, as a counteractive — because the default model for human behavior is unthinking and wishful, and that includes all of the noblest and most forward-thinking specimens of it. It's not about raining on the human parade; it's about reminding us that all our great works might well merely bear the name Ozymandias, and that we need to remain forever conscious of our motives for doing anything, even things we think will benefit us. (From what I see so far the stories in the Hieroglyph anthology understand this distinction, but I'll save a deeper discussion of that until I'm done reading it.)
Lem touched on this a great deal in his work: how even in our grandest work as a species, we remain pitifully unaware of just how much our egos and our self-importance is really doing the driving. In Solaris a scientist is sent to examine a planet which has a way of bringing to life the deep-seated desires of the sentient beings that come near it; all of the technology and technique at their disposal can't save them from the fact that they want the impossible. In the case of the main character, Kelvin, his dead wife manifests to him — and he knows it's not "his wife", but that doesn't change the emotional attachment he still has to even this projection of her.
Side note. Now that I think about it, it also helps to draw a distinction between being cautionary and being paranoid, because again I think the tone and the motives matter. Michael Crichton was cautionary at first (The Andromeda Strain), but devolved by degrees into paranoia (and revolting xenophobia: Rising Sun) later on in his career. His work became motivated less by compassion and curiosity than by cynical cleverness and contrarian fear-mongering. It's this kind of techno-thriller of the Tom Clancy neo-militarist mode that I find far more odious and harmful than any number of visions properly labeled as "dystopian".