For years, the seemingly unstoppable Marvel Studios built a reputation for family-friendly, PG-13 superhero fare. But recently, the Walt Disney Co.-owned unit has stumbled. The hit machine isn't cranking out box-office winners as it once did, a consequence of changing viewing habits since the pandemic, a perceived drop in quality and a glut of Marvel streaming shows and movies that stretched the audience's patience. On Friday, Marvel will turn to a different crew of superheroes to reignite its brand — the R-rated, irreverent and decidedly not family-friendly duo of "Deadpool & Wolverine."