This is true, but it's unfair to generalize all Science Fiction in this way. It doesn't really matter if what you write about is plausible or even possible. It doesn't even matter if it's already happened. A good story doesn't need to be completely fictional to work, because the strength is in the story you tell, not the technology in the world you've created.
As a writer of science fiction myself, having originally set most of the developments in my story to occur and mature over the next century, I was surprised when told that my book was being used as a technology primer for the military to explain the level of technology development of existing applications with respect to virtual world military testing and AI development.
I don't see this as "Well, there's no point writing this anymore, because I got it right" - I see this as more "I'm glad I got it right and now I can concentrate more on plot development in subsequent stories and less on the technology".
And just because what I write is based on factual technology, it doesn't mean it isn't science fiction. The exact genre is "Technothriller" but it's still science fiction.