Novel slavery...

But how did they get to become high civilizations? It isn't a coincidence. While resources help a lot, they also hinder. Why? Because when resources are abundant, people tend to sit on the resources and rely on them. It's like would you be more efficient at a job if its optional or if your life dependent on it?

Lack of resources have prompted civilizations to use resources more efficiently, and the more efficient you are, the higher your civilization is.

It isn't. Elves have natural adaptation to any forest. Beastkin's feral instincts, coats, good hearing, good smell, sharp claws and etc.

If I were to leave an elf child, a beastkin child and a human child in the wilderness, who has the least chance of surviving?

For the beastkin and the elf, that is like leaving them in their own backyard, they will survive without any issue unless they have bad luck. For the human, they are pretty much dead as humans have no natural weapons and our senses are no way as good as the other 2.

BUT, let us say all 3 did survive. Which of the 3 would you say progressed the most? That's right, because for the human, a lot more effort and a lot more creativity would be needed to survive and that need spurs growth as a civilization.

To put it simply, humans have the worst starting specs, but have the most potential for growth. 

In a lot of isekai novels, other races usually aren't that much stronger than humans. In "Death Mage" for example, most of the gods favor humanity by a much larger margin than other races. This allows humanity to constantly have more population, and more population means that the exeptionally strong individuals crop up a lot more compared to other races; allowing humanity to keep winning all the wars (again, with the help of the gods) and enslaving other races.

In another novel "Hakai no Miko", other races have min-maxxed stats that aren't so meta in their world. Elves are good with archery, but their arrows can't pierce human's shield. Dwarves are good with making fortification, but they're bad when being attacked at range. Basically, humanty is this "jack-of-all-trades" race that can adapt proper strategy against each enemy's speciality.

In most novels, humanity is this race with the favor of gods or the only race that could have heroes. This used to be a kind of satire to the even older novels where humans are that race that could defy all odds with their overwhelming heroism (there were a lot of those, and there are still a lot of them to this day). The first novels to depict humanity as this greedy race that enslave everyone probably made it to turn the view points around. For me, this was an interesting idea for a while until all isekai does it.

That said, it's not like all fantasy work does the same. Take "No Game No Life" where humanity is the weakest race by a long mile. 

Typically the other races have some sort of great weakness to make up for their great strength (arrogance, low birth rate, not wanting to stay together, etc) while the humans don't have any great strength but no massive weakness either which allows them to create (in most novels) massive empires full of lots of people and power. In the end because of the other races either being arrogant enough to believe themselves far above humans until humans become too strong for them to fight or their self imposed isolationism humans are allowed to spread and become massively powerful and thus able to subjugate the other races. Thus even though the other races are far advanced in some subject compared to humans they simply can't compete because of the massive weakness their strength leaves while humans can do just about anything with just a lower efficiency. 

Let's leave aside the fact that the author can enslave whoever he wants. Why would a proud and strong race as the elves turn into slaves?

They can be not that proud and not that strong, but the problem can be that they are too few, and are easy prey to hunters when they are doing their elvish things in the woods.

Or they live in small villages that are easy prey to large groups of hunters or even armies. Living long lives makes them a race with not a strong attachment to mundane things, like sex and reproduction, or even make them have low fertility rates and that would result in them being few and

And they can be made slaves by other elves and sold as merchandise by enemy elvish tribes. You know, the flute-blowing tribe hates the long-eared tribe, and they wage war every year during the hunter moon. Those that aren't killed are enslaved and maybe even sold to despicable humans (because of money).

Having low birth rates, living in small villages, they aren't that a warrior race and are easy prey to slave-hunting.

They are strong as individuals as hunters, warriors or sorcerers, but are weak against groups. They have no cohesion as groups, cannot work under a hierarchy, they have no strategy against an army or group and that way they can be targeted easily, provided that you don't attack everyone at the same time.

Obviously, Tolkien disagrees. 

I wouldnt call acess to one of the most fertile regions something you work for. Inventions do not necessarily come with need but possibility. Does the west need more technology? No. Did our technology advance more in the last 20 years than in the 2000 before them? Yes. Many advantages such as location are not something you have to work for. 

They could be blind fanatical traditionalists. Like "we have done things this way for the last 3 million years, and that's how things will be done for the next 3 million years," refusing to change the way their settlements were done or even their place. 

The weakness of elves in most fantasy is that They can't breed nearly as fast as humans do. They live long life and become lofty due to passage of time.

To be perfectly honest the amount of damage humans can do is insane , take tzar bomb. 

So the conclusion is that every other race, other than human, is f**king stupid.

Got it!!

They cannot adapt, they cannot think differently, lazy, don't want to learn new things, their bloodline already limit them and author and plot device. That's it.

*sigh* poor other race....