>It matters because once a person is a few years away from moving out, going to college, and starting a career; they need to starting learning how to live their lives for themselves, and not for their parents. <
And having a part-time job, or being in sports, or "involved in the arts", will do a better job of preparing someone for life than helping their younger siblings? Wow... what color is the sky in your world?
As far as "living lives for their parents", I've seen FAR more people involved in sports at their parents instance than I have kids being "indentured servants" and taking care of younger sibs. Odd thing: the ones taking care of younger sibs seem FAR better adjusted than Johnny Football Star...