Single family homes are very much standardized. You get doors in one of 6 widths (IIRC), and they are all the same height (closet doors are a different height, but otherwise standard). You get windows in a few dozen sizes. You get your wall studs in one of two lengths. And so on.

There is a lot of variation of layout possible within the constraints of the standard. However the vast majority of the hard work is done in a factory to standard sizes, and the onsite work is just final assembly to easy to change specs, so there would be no advantage to a standard.