What's NOT American about 'Ol Godzy? He's BIG, LOUD, takes threats and enemies and stomps them underfoot, and he's nuclear-powered. He doesn't back down or run away from a fight, and to top it off, he loves his kids.
Besides, I bet he'd make more money here. The budgets for his films in Japan are about HALF of what a leading actor makes just for himself per movie here.
Hell, just think if he decided to go into pro sports. What a linebacker he'd make!