Christopher Nolan’s next movie “Oppenheimer,” a $100 million-budgeted historical drama about physicist J. Robert Oppenheimer and the creation of the atomic bomb, could be considered one of an endangered species. These days, it’s rare for traditional studios to pump nine figures into a film that isn’t inspired by popular toys, novels or comic books. Even before COVID-19 upended the moviegoing landscape, audiences had been gravitating toward superheroes and science-fiction spectacles — and not much else. That reality has made it increasingly difficult for Hollywood to justify the economics of greenlighting expensive movies that aren’t based on existing intellectual property. They’re a bigger risk, not only in recouping investments for studios,…