Parent's Day

According to my calendar, today is Parent's Day.  I don't mean to sound like Scrooge, but doesn't this seem like overkill?  I have friends who think Mother's Day and Father's Day are plots by the major greeting card companies to boost their sales and, while I'm not quite that skeptical, I do find myself wondering about Parent's Day.  It seems to me that parents are pretty well covered with Father's Day and Mother's Day.  I appreciate that there are all sorts of family combinations these days.  When I was selling real estate, I sold a home to a family comprised of a woman, her ex-husband, her current husband and a child, but even there any of the parental types would have been covered with a Mother's Day or Father's Day card.  And don't even get me started on Children's Day.  Isn't every day Children's Day?