People take care of their families because of a bond that has nothing to do with blood. That bond is uniquely about mutual feelings and as a parent we have only a few years to make that bond last a lifetime.
If it's formed on top of obligations and resentment it'll break the first chance it gets. Just take a look at one of the kids in the article: she probably had a great life materially, but the minute she turns 18 she's willing to never talk to her parents ever again.