Your question ignores the reality of the twelve shvatim. Each with its own personality, its own sanhedrin, in some instances a definable different pronunciation of words and according to the Arizal different nuschaos hatefila.
Having separate smaller groups is not necessarily a bad thing. I will relate a drasha I heard from one of my rebbeim in beis medrash. While at Har Sinai, the Torah describes the state of the fledgling nation as being at the apex of unity, as one man with one heart. And yet the medrash tells us that when klal yisroel saw the angels parading in separate groups, each with their own flag, Klal Yisroel requested to be separated into tribes and Hashem agreed. What happened? Isn't this disharmony in action? And the answer given was that for each person to feel special and connected to Hashem they need a clearly defined role as part of a smaller microcosm, not to feel like one drop in an endless sea of 600,000, but rather to be part of the smaller group of the tens of thousands. As long as we all recognize each other right to worship Hashem in that person's group and associated style, than diversity can be beautiful. However, as far as interaction between various groups go, most orthodox denominations will not accept a group as being part of Jewish diversity if that group ignores the basic tenets of Judaism, such as adhering to halakha. And the vast majority of orthodox groups do not actively try to convince any other orthodox group that they are soley correct, and that the other needs to change.