Article continues below advertisementHollywood isn't just revisiting the past, it's building its future on it. From Miley Cyrus stepping back into her Hannah Montana wig to legacy sequels from Arnold Schwarzenegger and Sylvester Stallone, nostalgia has become one of the industry's most powerful creative and commercial forces.The strategy isn't subtle, and it isn't slowing down. But according to experts, it's also not accidental.