Employers are ordering workers back to the office. In recent weeks Dell, a hardware-maker, and JPMorgan Chase, a bank, have issued such decrees. They join a growing list that includes AT&T, Amazon and even the American government, where Elon Musk—who has called remote work “morally wrong” and its supporters “detached from reality”—has championed the shift. Bosses insist that mandates will boost productivity. Workers see them as a way to cut staff without mass firings.