You ever see Gypsy? (If not, and if nothing else, please revisit Kurt's showstopper in "Laryngitis" from Glee's first season.) You remember I Know My Kid's a Star from a few reality seasons back? Did you brave Living Lohan?
Those shows will learn you fast on stage parents: People driven by fame, fortune and perhaps their own shortcomings to seek out the spotlight for their children.
The Smiths individually, and as a couple, have their own fame, fortune and careers.
Are they going the Ron Howard route of raising their kids outside of Hollywood? Obviously not. But that doesn't mean they're pushing their kids into Hollywood. (And, by the by, the Howard kids weren't exactly barred from their father's sets.)
Feel free to debate whether Jaden Smith is too young to be a box-office star, and/or Willow Smith is too young to be dubbed the "next Michael Jackson." The fact is we won't know the answer until they do.
For now, all we know is Will Smith and Jada Pinkett Smith are not stage parents because they're parenting children who have taken to the stage.
Just like their parents.