Caprica may have failed, but shows like the Doctor Who franchise are still going strong. (Although there was a dip in ratings after Tennant and RTD left). I'd say that has some space opera elements, as there's the whole going to distant worlds thing as well as time travel.
Neither of those amount to a blip in the big pool of American TV. (And neither does SGU, assuming it survives much longer.) Space opera is for all intents a dead genre.
I disagree. Star Trek 2009 had strong box office showing. For all its flaws, I and many people enjoyed it. You put together a team to create a TV series that can tell compelling stories, set in the Star Trek universe, people will watch. For me, I was not crazy about the fx, and some of the sets, but the people kept me interested. Well except for Nero. If people watch the show for the story and characters, not the eye candy, it will succeed. Take TOS for example, people still watch it. New people become fans everyday. Even with it's outdated sets and effects, the stories and characters still speak to people. The same is true for much of TNG, DS9, some of Voyager and Enterprise. I think they went wrong when they lost site of the story and characters and focused so much on the setting. The same thing that Lucas focused on for his prequel trilogy.