Any theory, that has to develop in to a religion, system- it should focus on the principle formulation of existence of Human- How is it ? How it should be ? They should make the people to believe that their formulations are the truth and ultimate destiny.
That means- Why the persons get born? Why they live? Why they get Death ? What is before Birth ? What are the consequences after Death ? Which type of living leads to which type of result ? What is the cause for the present behavior ? How can we get health and happiness ? How do they go off ? - type questions should be answered. Then only they should be established as a religion, a path to be followed, a life style and thus they can attract and deceive the people and they assimilate in to them.
Through this type of process only so many religions, ways, lifestyles were systematized in the present and past on the basis of so many theories. These theory based systems stress them selves as the truth and ridicule the others.
If we observe them, this preaching process is simply trifling and their propaganda resembles to the companies publicity which serves the physical needs.