There is no iron scripture saying this has to be the case. Schism is mostly true today but not always, and it is absolutely optional. It appears to be endemic because of the American independent spirit and relative isolation during the 18th and 19th centuries, however Americans are no longer so isolated. The attitude prevails currently that each must be bible based, however this proud attitude can soften.Every Christian sect claims to be bible based, but they all disagree so strongly that they have to be in schism with each other.