When “Unchained Melody,” also known as the music from the pottery wheel scene in “Ghost,” shows up in a movie, it’s clearly meant to evoke romance.

In the teen high school comedy “Booksmart,” a bubblegum-pop cover plays when Molly takes her bestie, Amy , to the airport to leave for a gap year. Having a crush is still part of the movie’s angsty teen equation, but the song choice signals something new: that deep friendship isn’t a fallback but a relationship as important as romance. It’s a recognition that feels long overdue.

According to t he Census Bureau , the number of unmarried Americans 18 and older has risen to 45 percent, meaning there are more single people now than ever before. And more American adults today are valuing close friendships and career over marriage.

Some of this summer’s most talked-about films, like Olivia Wilde’s “Booksmart,” are starting to catch up to the reality of these demographic shifts, knocking romantic fulfillment down from its pedestal and exploring the richness of platonic pairings. Big-budget studio movies like “Once Upon a Time … in Hollywood” and indies like “The Farewell” hinge on the close bonds of their main characters and have performed well at the box office despite the absence of a dominant romantic story line.