Despite the influence of monotheistic faiths. How has Hinduism survived in India?: https://www.reddit.com/r/AskHistorians/comments/at1cwz/despite_the_influence_of_monotheistic_faiths_how/ by u/artfulorpheus

Why does Hinduism still survive when all other polytheisms have died out?: https://www.reddit.com/r/AskHistorians/comments/yfbcd/why_does_hinduism_still_survive_when_all_other/ by u/Daeres

This is a highly complex issue which reveals the deep importance of philosophical/theoretical approaches to history has on how we interpret the past, as there multiple contradictory theories. The history of religions can be a touchy subject. There is one particular approach not mentioned in the links given or the post by another which appears removed at present, but takes a particularly unique theory.

You might want to read some books or articles by Alan Strathern. He has argued a reason for the survival of Asian religions (excluding Islam) versus the, in some portions, complete collapse of pre-Christian African religions was due to the transcendental claims made by Asian religions versus the immanence emphasis of African religions. Immanence beliefs are not only more easily subjected to change when world circumstances change (think Cargo Cults), but also conversion -- as understood through that framework -- would not inherently radically alter beliefs. Transcendental beliefs, however, are more difficult to change with circumstances -- given the non-earthly stress and (comparative at least) permanence of the transcendental -- and changing them would involve serious reorders of belief and culture. It is a very interesting analysis, and one which opens up plenty of fascinating cross-cultural comparisons. However, it is only one among many, and the broad grouping of African religions as immanence and lacking transcendence should be critiqued.