I wonder what % of their members came from taking in orphans/foundlings or the children of unwed mothers? I have to think that would have decreased drastically as birth control and abortion were accepted, also the scandal of getting pregnant without being married becoming less of a big deal. Maybe the advent welfare state probably made the Shakers less attractive as people didn’t look at as a place were at least you would get fed.
Freegards
I don't recall seeing any numbers, but the children reared by the Shakers had an open door to depart when they reached adulthood.
The Shaker movement was a product of its times, but it seems to me that it could work for our times, too. People seek security in times of economic and social uncertainty.