So is it that the real future appears to be boring, so we prolong space opera instead? Such a non-solution -- space opera is often boring. Look at how they've prolonged Star Trek into really sleep-inducing stuff like "Discovery."
Back in the days of the Golden Age of Capitalism, or maybe a little earlier, the assumption was that some sort of technology would be invented, or anomaly would be discovered, that would allow ordinary human beings to travel at speeds faster than light. "Man" would then "go out into the stars," and discover the universe portrayed in Star Trek, in which extraterrestrial life appears as other people with new and fascinating ethnicities, and other planets as exotic versions of Earth. But they couldn't be too exotic -- imagine the cinematic difficulties of portraying a planet with two-thirds, or one-and-a-half times, the gravity of Earth.
And then you had the Star Trek fantasy technologies. There's no way the Star Trek "transporters" are possible.
The Star Trek universe thus developed into an elaborated version of the Marvel Comics universe. Space opera developed into fantasy, Fifties and Sixties fantasy, and (to be honest) fantasy that only remains interesting today insofar as it suggests the current state of the world. People care about galactic empires because real-life empires have not entirely disappeared from the world.
The failure of SETI to find anything of interest brings up another speculation:
www.mic.com/impact/the-milky-way-is-probably-full-of-dead-alien-civilizations-according-to-physicists-53931796So they destroyed themselves, or so the speculation goes. How? One obvious answer came to mind: their technologies were at best capable of producing societies that were addicted to fossil fuels. Once the fossil fuels were used up, their civilizations disappeared. And that was the end of the story for them.
