[Kuruharan]

I think small numbers are a hallmark of Tolkien's Middle Earth.

Nobody is suggesting otherwise.

However, an army of 10,000 is by no means an unreasonably small force and is in fact quite respectable. Calculate that back to the number of people in Gondolin who were not warriors and you arrive at a population of no mean size or significance.

Gimli's statement that only 1/3 of Durin's Folk were women and that not all of those married would also be representative of a population that is small and hard to recover numbers from disasters.

But there were many years between many of those disasters, which is plenty of time for some population rebuilding, even among slowly reproducing races.

A reasonable explanation for this was that in comparison with other kinds of folk they WERE few in number.

Which brings up the point of they could have turned up in numbers of 10,000-20,000 or more and still appeared "few" in comparison to the other armies of Free Peoples. And who is to say the amount of his total forces Durin sent to war in comparison to his total army? He may have only sent a picked force that was not truly representative of the size of the army he could have fielded. Perhaps that was all he was asked for...or perhaps being a dwarf, and dwarves usually having a shrewd idea of what their interests might be beyond the interests others think they should be, he may only have sent what he saw fit. I don’t recall if its explicit from the text that the king even went himself.

The Haradrim Chief and his horsemen are said to have seen Theoden and that few of Theoden's men were about him. Theoden "becomes aware" of him and though "fewer in number" their superior knighthood routs the Haradrim.

Again I must beg to differ with your reading of the text.

Southward beyond the road lay the main force of the Haradrim, and there their horsemen were gathered about the standard of their chieftain. And he looked out, and in the growing light he saw the banner of the king, and that it was far ahead of the battle with few men about it. Then he was filled with a red wrath and shouted aloud, and displaying his standard, black serpent upon scarlet, he came against the white horse and the green with great press of men; and the drawing of the scimitars of the Southrons was like a glitter of stars.
-The Battle of the Pelennor Fields (emphasis mine)

Sounds like the Harad chief had lots of guys with him.

Not that it really matters to the overall point I was trying to make above.