You're describing content, not form. Many websites also have to show the same things (login button => speedometer) but they don't have to look the same.
Most websites want their navigation to be found, so they put it in the same place as every other website. They want their story easily readable in the center.
There's still plenty of variation, but sites with similar goals are going to end up with a lot of similar elements.
Being different for the sake of being different just wastes people's time trying to find stuff that isn't where they expect it to be.