I think it's hard to pinpoint cause and effect here. Science fiction in the golden age was the product of an interesting coalition of nerds, dreamers, rocket scientists, hippies, and idealists. It was a product of a very optimistic age, and it was also built by, and for, a niche audience.
Most of what passes for sci-fi today is a far more mainstream product. Mainstream products tend to closely track pop culture, which to a large extent, tracks socioeconomic conditions. Today's stuff is really just romance, thriller, or adventure tropes with sci-fi window dressing. The recent fascination with dystopian futures reflects the current zeitgeist to some degree: we're living in a more uncertain, economically unstable age than the sci-fi writers of the 40s through 60s were. Everything was looking up-and-up back then,[1] and the sky really seemed to be the limit. These days, people are more skeptical and more concerned. We are getting a literature (and cinema) that is equal parts fear and escapism.
It's certainly possible that dystopian sci-fi is creating a feedback loop, and that it's making us more scared and more cynical. But I don't see compelling evidence for a causal or directional effect there. More likely the directionality is the opposite: people seem to be buying that stuff, and so the publishers in the market select and publish more of it. What we're seeing is largely an artifact of selection -- by the publishers and studios, and accordingly, by all the dystopian stuff floating around in pop culture.
I wholeheartedly support the call to action in the article, namely, that "It's time for us to dream again." But that's easier said than done. The market wants what it wants. Publishers want what the market wants. Few people are in a position to challenge that consensus. Perhaps it will take a few breakout hits of a more optimistic, exciting, less morbid vein to change things up a bit. I would certainly back any ambitious Kickstarter projects of that nature.
[1] A notable caveat is that Cold War nuclear paranoia played a discordant note in the overall melody here. The effects were interesting, and the interplay between bold optimism and end-of-the-world panic made for a rich and complex output.