I've just finished reading H.G. Wells' "The Sleeper Awakes" (aka "When the Sleeper Wakes") - first published 1899. So the first thought that popped into my mind when I saw this thread was that the times keep changing. I could sit down now with the same basic plot (man goes to sleep for 200 years and then wakes up to find that he's master/owner of the world) and come up with a totally different story. Not just the language used, but the society I live in now is so different that the world I would envisage in the future would be very different. (I remember having similar thoughts when I re-read "War of the Worlds" recently, I got to where the artillery-man describes what the world might become under the Martians and I wanted to write that story.)
The immediate follow on thought is that a dozen of us here could pick up that same basic plot and come up with stories that felt completely different. Even if we tried to duplicate Wells' tendency to comment on trends in society - we all see them differently and have different priorities.
It's easy to look around and think that everything has been done, that there's nothing new under the sun - and much of the time it's true. It might be a new idea to one author, but it's a reasonable bet there's a book out there that's touched on the idea in one form or another. There isn't all that much that comes out that's completely, or even significantly, original - even the absolutely wonderful Harry Potter series fed from many things that had gone before, and yet the mix was original.
It can also be argued that building on what has gone before is to your advantage. One of the things I've heard people complain about with fantasy is that they get frustrated waiting to learn enough about the new world so they can get involved in the story. When you build on what people already know you get to jump into the story more quickly. One of the things that always surprises me when I pick up Pride and Prejudice
is how little description is given, it is assumed you know (and thanks to TV, I do
(Good) Stories remain feeling fresh and original not because the ingredients are necessarily original, but because the author has found their own way to present the story, and found their own mix of ingredients.
I don't know if Meyer's were the first sparkly vampires (I've not read widely enough in the genre to know), but they were certainly different to the more traditional forms I'd read before. Some mix ideas from different genres: vampires and werewolves in space; magic and science-fiction; the whole steam-punk genre. Some look at (essentially) the same story from a different participant - the serfs rather than the kings ... and so on.
And then there's just the difference in what sort of story it is at its heart. It may be set in space and still be a romance, a horror story, a murder-mystery or whatever. Is the story about the idea, the situation and environment, the relationships, or the events. Good stories are usually about all these things, but each writer has a different emphasis and that makes each story feel different.
Hmm... getting carried away here. I'll let someone else have the floor.