There is an interesting short story by Harry Turtledove, first published in 1988, called 'After the Last Elf is Dead', the world portrayed bearing a very obvious resemblance to that in
LotR. The scenario is where Evil has triumphed over Good, with an interesting result.
Some of that story can be seen online, in a collection of Turtledove's stories in Google Books,
Counting Up, Counting Down:
https://books.google.ie/books?id=nnm...20dead&f=false
It's worth a read.