Of course there are a multitude of reasons that tests bring out different scores, people adapt to deal with the world they live in and how it works, some will always be brighter than others.
It's the constant harking back that irritates me, my first job in a haberdashers was selling things such as ribbon - Three and three quarter yards at two shillings and eleven pence ha'penny a yard, calculated on paper with a pencil.
Not sure bemoaning the fact my Grandchildren would struggle with that proves anything.