Barbie” and Christopher Nolan’s “Oppenheimer” ignited the summer box office, the blockbusters with twin release dates are bringing populist energy to the Oscars. Yet the one-two punch of “Barbie” ($1.445 billion globally) and “Oppenheimer” ($957 million), along with a valiant assist from Martin Scorsese’s crime epic “Killers of the Flower Moon” ($156 million), can’t compete with the box office power of last year’s contenders. Led by “Avatar: The Way of Water” ($2.3 billion) and “Top Gun: Maverick” ($1.5 billion), the 10 films up for best picture in 2023 were collectively the highest grossing in more than a decade, racking up $4.4 billion worldwide.