The four major new religions featured in Harold Bloom's interesting book American Religion were Mormonism, Seventh Day Adventists, Jehovah's Witnesses and Christian Scientists.
All grew quickly and went international - and the first three continue to thrive and grow significantly, year upon year, now with teens of millions of members in a context where the major Western denominations are all in decades long decline. However, Christian Scientists are the exception among the four, and have been declining for many decades, much like the mainstream Christian churches.
Sociological explanations for the success of Mormonism, Seventh Day Adventists and Jehovah's Witnesses focus on their high time and money and effort demands on members, with relatively high strictness of observations - combined with considerable efforts at recruitment ('evangelism').
These factors are clearly important - but I think a neglected factor has been that the three successful religions are all 'Patriarchal' while the unsuccessful Christian Science was substantially women-dominated.
(The Seventh Day Adventists were founded by a woman Prophet Ellen G White; but the church has a male 'priestly' structure and traditional concepts of marriage and sexual complementarity.)
I think this is a confirmation of an important socio-political principle; because while 'Patriarchy' is clearly resilient, I do not think there are any examples of long-term survival of mixed sex institutions under predominantly female leadership - certainly not churches.
(Female institutions under female leadership - such as orders of nuns, or maybe some women's schools and colleges, have sometimes survived for several or many generations.)
How this is interpreted is clearly another question - and the explanations will range between opposite extremes; but equally clearly the evidence is that when any mixed social organization - including a church - becomes predominantly female-dominated, it will decline and dwindle.
Anyone with a valid counter-example is welcome to e-mail me and I will append it here.