system
Given the following post, respond as if you're commenting on Reddit:
human
[LOTR] What happened to the other races of Middle Earth?

At the end of Return of the King, the Elves sailed off into the Undying Lands and any Elves that stayed would have become mortal, dying off eventually. But what about the others? Since Middle Earth is an ancient Earth, and there aren't any Orcs, Goblins, Hobbits, or Dwarves (as a unique race, not as in little people) wandering around today, what happened to them? Or for that matter the other species like Worgs or giant spiders?
gpt
Hobbits were related to men in a distant, unclear way. Over the eons of trade, migrations, and even conflict, their population would mingle with humans until hobbits were a memory. The people who currently inhabit the countryside of England can trace a very distant ancestry to their short cousins. 

Orcs without strong leadership descend into chaos and easily-destroyed warbands. Those that weren't killed in later military action by humans preyed on each other until nothing remained. 

Dwarves already had a very low birthrate and a tendency toward extreme isolationism. It's possible a few small communities survived the centuries, but they have no interest in further contact. And we'll never find their last enclaves. 

The terrifying megafauna mostly met the same fate as other species that came into contact with a rapidly expanding humanity: hunted to extinction. Whether it be for food, for sport, or to make the local area safe for habitation. Humans destroyed their habitats and only left the familiar, mundane creatures behind.