Ok, a few things here.
First off, if the goblins do not have genetic memory how do they learn specific skills, like how to find, mine and smelt ore?
Second, why assume that the hobgoblin will act rationally and conserve his breeding stock?
Third, and I would assume that it would happen often, wouldn't the hobgoblin get challenged if he hogs all of the pussy for himself?
Also, from what Bear Ribs explained, it sounds like the goblins need periodic replenishment and divine aid to keep their numbers and not get exterminated.
Also, it sounds like every single instance where they managed to form something stable and more advanced was a special case, which is not something we can expect with any degree of certainty.Like you said, goblins had to be taught to preserve their breedingstock by an external force.
IMHO all that shows that your median, run of the mil goblins are pretty bad at self-organizing, and if they are ever put into a situation where resources are scarce they will probably devolve into infighting.
Was it ever specified if the Goblins got a kick of the actual breeding and if it was important to them to take part in breeding?
You'd think that with breeding stock so limited and thy having to raid for it then breeding must be even more important to them than it is to us, so not being able to partake in it just might make them rebellious or willing to run away to form their own nests.
So,according to you,that group of goblins would be not smart,and need divine intervention to survive ?
If so,they could just die off,thanks to smarter indians hunting them.And all which would be remain would be legends about raping monsters.
Or maybe not even that.Well,archeologist in USA would find smal bones and discover new homo species.