That's...not particularly true, especially for the denominations that are both large and institutionally old, or are newer but less centrally authoritarian. The Roman Catholic Church (for an example in the former category) for instance, has a small number of declared-as-infallible dogmas, a larger number of doctrines that arr understood to be certain or argued to have been infallibly declared, a wide space of broadly accepted doctrine about which there is still debate which is recognized as legitimate and not dissent, and plenty of open theological questions, more of which are added all the time, because changing circumstances raise new questions not previously considered, and change the factual context of previous considerations so that, even for doctrines that are solid, what piece of the prior articulation is the actual doctrine and what piece reflects the limitations of the context considered at the earlier time must be discerned, and is often actively debated.
