The biggest not-talked about issues here are leadership, envinronment, feasibility of such large numbers to wage a war and inclusion of magic. Battles are won by tactical and strategic positioning, environmental factors, psychological factors, technology, etc. Man for man, elves are far superior to humans. First Age elves especially so (as has been noted, first two ages, Elves stomp Humans horribly). However, millions of humans can be easily scared. They can easily lose heart for battle, after seeing thousands of humans die. They can be disorganized, become selfish (humans are arguably more selfish and less socially self-identifying than elves who have ridiculously strong vows and personal bonds) and they have inferior equipment and training. A large chunk of humans are just mooks and badly trained ones at that. For every well trained militia or general or archer, there's hundreds if not thousands of everyday people who are millers, barkeeps, fletchers, etc. These are not going to be of consequence unless they are stocked in the front row for slaughter, to be a meat barrier to the proper soldiers in the back.
In a somewhat sensible scenario, these untrained humans would hold the back lines and flee or be routed with ease. The actual fraction of humanity that is able to fight (which would include First Age clans, Second Age Numenorians) would put up a hell of a fight. Many many elves would die. But elves could possibly take the day if leadership is strong, they stick together, utilize their magic and archery and superior tactics intelligently. Top level elves have ridiculous powers that only the Numenorians could attempt to match. How long would humanity stand its ground when you have elf-lords butchering whole groups of men with concentrated arrow fire, ice-cold razor-sharp weaponry that is enchanted, and mystical powers one cannot understand?
In a straight up brawl, elves could not hold their ground. With some prep, a clear line of command, and proper usage of their strengths, it could turn into a rout.
That was awesome completely agreed!!! I can see you know a lot about Tolkien and his type of warfare (moral counts a lot) and as you sad individually only the Numenoreans can put a fight to the Eldar and even fewer of them against the Noldor and even fewer against their nobles.
For those who say dwarves and men are physically superior to the elves or that they were never described as strong beings:
"He was as tall as a young tree, lithe, immensely strong..." - Legolas
“…and they were tall and dark-haired and strong like fir-trees, and from them most of the Noldor later were sprung.
“…that time the Noldor still walked the lands here, the most powerful and most beautiful children in the world, and their languages were still heard by mortals.”
“…The Noldor, outnumbered and taken at unawares, were yet swiftly victorious; for the light of Aman was not yet dimmed in their eyes, and they were strong and swift, and deadly in anger, and their swords were long and terrible."
"Fingolfin was his father’s son, tall, dark, and proud, as were most of the Noldor."
They were called “halflings”; but this refers to the normal height of men of Númenórean descent and of the Eldar (especially those of Ñoldorin descent), which appears to have been about seven of our feet.’
'The Quendi were in origin a tall people. The Eldar (...) they were in general the stronger and taller members of the Elvish folk at that time. In Eldarin tradition it was said that even their women were seldom less than six feet in height; their full-grown elfmen no less than six and a half feet, while some of the great kings and leaders were taller.'
For the Noldor indeed were tall as are in the latter days men of great might and majesty.
They (Elves) were thus capable of far greater and longer physical exertions (in pursuit of some dominant purpose of their minds) without weariness; they were not subject to diseases; they healed rapidly and completely after injuries that would have proved fatal to Men; and they could endure great physical pain for long periods. Their bodies could not, however, survive vital injuries, or violent assaults upon their structure; nor replace missing members (such as a hand hewn off).
In general the Sindar appear to have very closely resembled the Exiles, being dark-haired, strong and tall, but lithe." The History of Middle-earth, vol. XI, The War of the Jewels: "Quendi and Eldar,"
Felagund put forth all his power and burst his bonds; and he wrestled with the werewolf, and slew it with his hands and teeth.
"The Númenóreans ... are in constant communication with their ancient friends and allies, either in the bliss of Eressea, or in the kingdom of Gilgalad on the shores of Middle-earth. They became thus in appearance and even in powers of mind, hardly distinguishable from the Elves..."
Sauron indeed achieved even greater control over his Orcs than Morgoth had done. He was, of course, operating on a smaller scale, and he had no enemies so great and so fell as were the Noldor in their might in the Elder Days. (Myths Transformed, Morgoth’s Ring)