[tsimionescu]

Sure, but the tinier the worker, the more effort you need to build a machine of a certain size. Even today, most construction of any kind has significant manual work components. We are pretty good at building things hundreds of times bigger than ourselves, but I'm not sure we would be great at building something a million times bigger than a human. Of course this is not directly comparable, since we are often limited by materials science before raw manpower if attempting something like this; a 2km tall skyscraper is fundamentally harder to build than a 20m one regardless of the size of your workforce.