As the father of 8 and 5 year olds I can tell you with great confidence that Nintendo games are the KINGS of gaming for many years to come in my household.
My almost 15yr old son grew up with only Nintendo but now is PS3 obsessed. He doesn't fancy the PS4 though and I think he would rather die than get an Xbox based on his teenage mutterings.
My youngest son is 5 next month and doesn't really care for games yet but I will only buy Nintendo for him if/when he does.