I thinking you're confusing causality here.
The vast majority have staying power because of two primary things. Have children, teach those children your religion. In the days before mass education and when huge numbers of children died in early age making this a memnatic was an important way for societal continuation.
This says nothing about it's continued usefulness after a paradigm shift.
Meanwhile many modern replacements usually don't have any longevity. Maybe one of them will survive but only time will tell.