I suspect that, because so much of the time required is either political or organizational, the part that's left (which would be expected to go up with increasi

I suspect that, because so much of the time required is either political or organizational, the part that's left (which would be expected to go up with increasing size) is not actually enough to make a very big correlation between size of building and time to complete. Which means "builds skyscrapers the fastest" actually means something more like "builds the biggest skyscrapers".