>>535483518
Hot and wholesome.
I have learned a lot from watching Japanese stuff and Chinese stuff.
Everything starts to make sense once you understand weird things like Main-family and branch-family is tied to 3-generation households.
If you're 5 children, you, 2 little brothers, 2 little sisters,
You become the main branch and hoard most of the wealth, your 2 little brothers become branch family, your 2 little sisters are married off to om other household,
from what I can understand, they won't be able to visit you anymore, they are kind of captives of their new husbands... I guess.
So they lose you, their big bro. You lose them, your little sis's.
But you get to adopt a new thot into your family, maybe the loss of your 2 sisters will cause you to see the new chick as your replacement sister, so you just call her your sister because you miss your real sisters.
I'm making alot of guesses, but I think it's very plausible this is how it was in many cases.