I played D&D all the way back from before the 1st Edition AD&D, from the faux-leather brown paper covered trilogy of books. Seeing how Gygax and Arneson based much of it on Arthurian legend, Middle-Earth, Earthsea, and Lankhmar, but particularly Middle-Earth, having cannon fodder for enemies makes sense as far as orcs, goblins, and kobolds. When my brother and I got his characters to level 9 and we moved into the Drow series of adventure modules, they were very definitely elite-level creatures, coming after the G (giant) series of modules where you took on masses of hill, frost, and fire giants.
Drow were truly kick-ass enemies, and you couldn't help but love them as opponents...I think there are very good reasons why they have captured the imaginations of gamers for so many years. I mean, after them, you went on to fight a goddess (Lolth) herself.
The funny thing is, since I DM'ed and my brother ran the characters, and he wanted to keep on with those characters, we needed to move on after that with them. They were roughly levels 11-14 by then, and the Manual of the Planes had been published around then, so he went on many varied and enjoyable adventures in Hades, Tartarus, Gehenna, the Hells, and the Abyss. Because what is left to do after taking on one demon queen...than hordes of demons, daemons, and devils--in their homelands?