This is how many urban residential neighborhoods built before the 1950s are. Mine in CA is a such a neighborhood built between the 1920s and 1940s - originally

This is how many urban residential neighborhoods built before the 1950s are. Mine in CA is a such a neighborhood built between the 1920s and 1940s - originally very similar 1000sqft Craftsmans that have been incrementally enhanced over generations up to and including including now. Where you find a distinct lack of this sort of organic variation is in suburban tract single family home developments where changes are micromanaged by neighborhood HOAs.