Much of India had also long barred cousin marriages, probably long before the Roman Catholic Church, but the dependencies and village raising the kids dynamic still existed (until recently).
https://en.wikipedia.org/wiki/Sapinda
If I were to guess, the main causal factor is economic/security independence. If living in a tight knit village, sacrificing your freedoms is the best option you have, then that is what most people choose. If there exists an option for you retain your freedom and have financial independence and physical security, then people tend to choose that (e.g. getting an education and a well paying job, etc).
The latter basically destroys any chance of “village raising a child”, because no village bonds will exist, since everyone is moving around for their economic opportunities.