Vanilla is a product of Lussumo:
Documentation and Support.
1750 is not only the year in which fantastika began to be written as a weapon against the owners; it also marks the point when Western Civilization begins to understand that we do not inhabit a world but a planet.
War of the worlds radio show - that would never have worked today.
Specifically, Lucian's True Story, an absolutely fantastic parodic science-fiction story written around, ooh, 160 AD,
The old adage that if it isn't broke, don't fix it, is largely what the publishing community holds true to, the editors and associated folk who make those books aren't really looking for the new, they're interested in sell copies of books that they can predict. I'm amazed Crooked Little Vein got released, primarily because it was so different then the rest of the crap on the bookstore shelves. Even Harry Potter (which was just old stories dressed up in a British Boarding School setting) failed to bring anything new to the shelves. Harry Potter was different, but rather than opening the floodgates for the new ideas, it just opened a small slot in the wall for stories about magical kids
The genres are dying in the public sphere primarily because the publishers don't want to take a risk on anything that they can't see coming. Corporate culture is destroying the creative imperitive. It's not that people aren't writing new things, they're just not getting published (at least I hope that's right) because they are new. The same thing that has happened to movies is happening to books. If you can't market a movie as a "well it's sort of like 'When Harry Met Sally' meets 'Psycho'" studios won't look at your screenplay, and if you're writing Fantastika that isn't "like" something else, publishers won't give you the time of day.