[Science Fiction has] been dominated for decades by a single storytelling dynamic. Instead of reaching for intelligence and stretching the boundaries of imagination, it decides to take hoary old clichés, lots of narrative formula, and one man's F/X laced legacy, and completely rewrite the rules of acceptability. Where once the speculative spectacle questioned the existence of man within the cosmos, today it's all Westerns with robot (SF Signal: Is Serious Sci-Fi Dying? via Big Dumb Object).
Serious Sci-fi is dying, eh... I have a problem with this question in and of itself. Let me first share the list of Series Sci-fi given as an example.
The Twilight Zone, The Outer Limits, and The Star Trek Saga (including all recent TV incarnations), [...] - Planet of the Apes, 2001: A Space Odyssey, Soylent Green, Close Encounters of the Third Kind, Brazil, Dark City, The Matrix, and most recently, Children of Men
-[...] Silent Running, Solaris, Blade Runner, Gattaca and A.I.: Artificial Intelligence (SF Signal: Is Serious Sci-Fi Dying? via Big Dumb Object).
OK... So the question is whether Sci-fi that grapples with major Questions about life and the nature of things as they are (I would drop Brazil, Dark City, and Children of Men from the list).
Well is Serious Sci-fi dead? Yes. Everything goes in cycles, there is nothing new under the sun, and we are in a phase where horror and thrill have become primary in the market (whether that is what audiences want or not). The industry follows the money. The flicks that are making the most money are action thrillers with a lot of unnecessary gore and obsessive sado-masicism, so the market follows suit.
This is why Heroes and Battlestar Galactica are taking the media by storm. Watching people suffer is replacing watching people struggle with issues of life and philosophy.
This is a cycle, it comes and goes. In the meantime, writers and artists that remain true to their vision (ahem) are still trying to tell thought provoking stories in entertaining ways.
Keep the faith, this too will pass.