It's very true that one mother or woman can take care of many children, including those she never gave birth to, but if it's the other way round, all we can hope for it that she finds a way to take care of herself once she is old.
I doubt the mom of these little ones ever thinks about this fact. She simply kicks out the little ones or they leave. It's the circle of life. They don't have offspring with the idea they will take care of her.