Why is modern kid's culture so weak and wimpy?

My son and his friends are in 3rd and 4th grade and they all like Disney stuff and SpongeBob and Minecraft and other weak inoffensive stuff like that. When I was that age, my friends and I were into WW2 and Medieval history and the Wild West and making weapons and horror movies and post apocalyptic science fiction. Why the huge change for the weak and wimpy in children's culture over the last few decades?

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