The goal of Vaishnava Hinduism is to achieve self-realization and to live life based on that self-realization. It is not something that one joins, but rather it is a path with particular practices that one follows.
Vaishnava Hinduism should not be equated to a “religion” like Christianity, Islam, etc that one can join, convert to, or quit. The very essence of Vaishnava Hinduism is the principle of self-realization; and self-realization means understanding that ultimately one is not the physical body, the mind, nor any designation that one may apply to oneself.
In the yoga system, the seeker of the truth inquires from a person who is actually self-realized or enlightened in order to be taught and guided by that teacher. To be considered a bona fide teacher, one must be in a recognized disciplic succession (called parampara meaning “one after another”). In this way, the spiritual teachings and practices are handed down from spiritual master to his disciples, and then those disciples in turn pass it down to their disciples, and so on. It has been this way for thousands of years. Often, each disciple who achieves self-realization will start his own mission to carry on the teachings and traditions he received from his guru. Consequently, from one founding guru or acharya in a particular disciplic line who taught hundreds of years ago, we may see today thousands of individual missions and ashrams representing his teachings.
The lineages do not represent the continuation of a large institution which grows and expands through time as we see in most world religions, but rather, is a continuation of teachings through individual self-realized teachers.
Therefore, there are often countless branches within a particular tradition or school of thought. These branches are not breakaways or “splinter groups,” rather they are all part of the same tree.
Thus, the Hindu Vaishnava system is, by its very nature, very decentralized and diverse.