23skidoo said:
certainly not every one of the films listed in the OP are original either.
Most of them are derived from some other source, actually...
THE DAY THE EARTH STOOD STILL -- based on a short story
WHEN WORLDS COLLIDE -- based on a novel
THE WAR OF THE WORLDS -- based on a novel
FORBIDDEN PLANET -- based on 'The Tempest'
INVASION OF THE BODY SNATCHERS -- based on a novel
STAR TREK THE MOTION PICTURE -- based on the television series
PLANET OF THE APES -- based on a novel
2001: A SPACE ODYSSEY -- based on a short story, 'The Sentinel'
Of the three that remain, if you expand your criterion to 'influences' you're left with even fewer 'original' films...
FANTASTIC VOYAGE – original
ALIEN – original (though indebted to IT! THE TERROR FROM BEYOND SPACE)
STAR TREK -- original (though indebted to FORBIDDEN PLANET)
My point, I suppose, is not to be pedantic, but to indicate that 'originality' in the sense that you seem to define it isn't all that useful. MOON might be compared to SOLARIS, but it's by no means the third iteration of the Lem story, but something quite different. That a work of science fiction carries the markers and influences of other films in the genre (and of other genres) is inevitable at this point. If those are grounds for dismissing work as unoriginal, well, you'll be left with nothing new at all from the genre at this point.
That was less too the point than I wanted it to be, but seeing as I just typed out that list, might as well go forth...