Originally Posted by
parabellum
Boeing build the aeroplanes but the customers decide on their required seat config, toilet and galley placing etc. Whether you get a window or not is down to the airline.
That's a bit of a cop-out. It's quite apparent, comparing external views of Boeing and Airbus fuselages, that Boeing are quite happy to have blank cabin walls at points where one might typically expect seating, an aspect which Airbus manage to avoid.
And regarding toilet-galley placing, although flexible that is driven by airframe provision for plumbing connections, tank location, etc.