Greed makes people crazy and nothing makes people greedier than a certain precious metal. In “Gold” (2022), Zac Efron finds himself in a version of “Mad Max” with much fewer contraptions. Hobbled but still optimistic, he hitches a ride across this dystopian wasteland, where he and his cohort stumble upon the unexpected. Predictably rapacious hijinks ensue. Zac starts out needing a bath and as the film drags itself into “Revenant” territory, I stayed interested by wondering how much dirtier he’d actually get (you’d be surprised). You probably won’t be surprised by how this painfully tedious exercise in degeneration turns out.