Exactly. So the positive and negative feedback
from your own actions creates an
accelerated learning loop, and, if you're equipped with enough desire for improvement, you quickly gain at least a hundred more of actual skill - quickly followed by elo itself once you start pwning the other guys with swift vengeance and unforgiving precision :P
This of course implies that you go as far as to watch replays and see what mistakes you made, etc. Some people just don't learn and stay at 1200 elo even after a thousand battles, always doing the same "porc my simbaes" ploy.
Anyway, you're too categorical on "one mistake" part, too. There was that
tournament game where a guy who lost his only factory THREE TIMES (rebuilding each time), lost his commander as well, and
still came out on top - want to see the replay?