system
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human
[General Fantasy] How have orcs and goblins not been driven to extinction?

A common and rather valid criticism of orcs, goblins and just the “inherently chaotic evil species ” trope in general is that they wouldn’t be able to survive very long. Either wiping themselves out by their own violence and stupidity or other races just getting tired of their pillaging and violent antics and banding together to genocide them out of existence.

Let’s not examine the more morally complex orcs and goblins archetype, simply looking at the innately evil orc and goblin archetype. The roving, warmongering hordes of perpetually primitive, innately evil and violent morons serving the dark lord. Pillaging, destroying and eating everything around them in their never ending lust for battle.  How would a species like evil orcs survive for any length of time? What stops either themselves or others from driving them to extinction? 

The only things I can really think of is them being really fast breeding. Them being much more physically capable making them tough to fight. And being nomadic and living in hard to reach places making orcs and goblins difficult to track down.
gpt
Orcs have a habit of being very difficult to kill, and fantasy races are famously reluctant to band together around anything. The breeding rate is also likely to be high, as you mention.

I can’t speak for specific stories but, in general, orcs and the existence of evil as a whole is often a result of the good guys being unable to work together.