Yes, why indeed should it be more taxing on a human mind to concurrently control a cast of a thousand PCs than a single one of them? Plainly this was not an issue that ever needed resolving.
For me, it wasn't - and I play quite a lot of war/board games too. But when I play an RPG, I want RPG, not a wargame. When I'm GMing, my NPCs aren't fighting interesting, because they are using Attack #17, but because I devise interesting tactics/gimmicks for them - for example, if there's a mutant with tentacles, he jumps up and uses the tentacles to stick to the ceiling, then next round - falls on a hero. I love devising this shit for my encounters. Or the skeleton the party faces? He delivers a slash to the forehead, causing blood to fall over PC's eyes - -20 to attack rolls.
After a while, PCs also picked up an idea that imaginative and descriptive hits are better then just "I stick him with the sword." And that was done in Warhammer, so you had some skills (such as Strong Attack) to handle the invention for you.
True, but since I never used mini's with any other version of D&D, after setting up the dungeon tiles and placing the figures, it FELT more like I was playing a game, if you catch my meaning.
I use minis a lot, Werekoala - they help me. Last Saturday, the PCs split into 3 parties, chasing 3 different groups of kobolds. But I mostly use minis (or well, paper cut - outs) as references - I don't use movement mechanics, for example. Just my arbitrary opinion if "you are in charge distance", or not.