Different folks want different things. Though as time goes on more and more houses look different in style in the same neighborhood. There are limits though - there are only so many ways you can do a garage and the required drive from it to the street so that always looks similar.

Most builders of spec houses intentionally buy just a few scattered lots in many different neighborhoods - that way they can build the same house they always build, yet not neighborhood has two houses that look alike. But there are neighborhoods where all houses are built exactly alike...