Ford introduced the assembly line, which apparently cut production cost drastically.
Interestingly, though, I heard that years ago, the Hasselblad camera factory in Sweden experimented, and they found that by having workers compile a bigger part of a camera instead of repeating the same tiny action again and again, things were more efficient and people made fewer mistakes.
(Isn't it amazing to see that fragile-looking car handling terrain like a hummer?)
I love the model T. For me it has (along with other cars of that time) a presence which modern cars just don't have. I don't know why. (I can say the same about airplanes.)
I once sandblasted the body of a Ford Model A. Try doing that to a modern car, and you'll have the plates curled up like wet cardboard.
Jay Leno is a car buff. Here he talks about how good the model T is to use even today.