For people who where not alive at the time you have no idea how hard and fast that hit - Honestly I was to old for it an my sister was towards the middle or tail end of the intended age group for it but EVERY child in that age group went from overnight knowing nothing to being utterly obsessed, it was on TV all the time, the Toys, the Games, the other Merch was everywhere and it was for a few years before it even died down slightly.
I hate terms like "Caught lightning in a bottle" but Nintendo certainly did, and I can see why someone mentally younger than they really are an more simple than their age group like Chris would become a fan and stay one, it's marketing was almost perfect and had a toy or some other item to fit every occasion allowing it to be a 24/7/365 fixture in a childs life.