I believe you have hit on a good point.
There are probably more nesters (by your definition) still at home with parents than non dubs.
Economics is a big factor. Low paying jobs, lack of education, therefore lack of real career opportunities.
I believe that many of the parents are okay with ths arrangement, because they have crappy low paying jobs and they need their childrens income to help sustain their household.
I also believe that many parents think that if their children still live in the household, they are protected from having sex. Of course this is false more times than true, but it does give the parents a huge level of control, well past whats normal or healthly for their children.
But, what do you expect form a religion that controls every decision made by adults, in turn the adults tries to control every move of their children.