>>96103666
>Which we can see by how far humanity spreaded across the Milky Way durring DAoT
That was always a weird part of the lore and mostly the result of writers not communicating with each other.
The simple answer was always that Eldar had their webways everywhere, but their population was concentrated around the now Eye of Terror. Humans were simply regarded as something like local fauna that wasn't a threat to them at all. And they weren't.