Did the Black Death make workers richer?

Eventually, and for many of the survivors in Western Europe, yes, but not right away, and not everywhere. The Black Death, a plague spread mainly by fleas, killed up to 50 million people in the mid-1300s, somewhere between 30% and 60% of Europe's population. Suddenly there were far fewer hands to plough, reap and build. Workers who survived had bargaining power, and they used it.

The elites panicked. In 1351 the English Parliament passed the Statute of Labourers, banning anyone from asking for or offering more than pre-plague wages. The law grumbles that servants refused to work unless paid double or triple their old rates. Those who wouldn't swear to the old wages could be put in the stocks or jailed.

At first the law barely mattered, because inflation ate the gains: right after the plague, real wages did not rise, and many wage earners actually got poorer. But the shortage didn't go away. The statute was poorly enforced, and English farm wages roughly doubled between 1350 and 1450. For many Europeans the 15th century became a golden age of cheap land, high wages and the near-end of serfdom.

It had limits. In Eastern Europe, lords tightened serfdom instead. And when populations recovered a century later, the poor again faced hunger. The plague didn't make workers richer by kindness. It made them scarce.