“You’re on Mute!” Is the Phrase of the Year

Courtesy of the Financial Times, here’s a weird chart to start off our week:
What accounts for this? Corporate earnings calls, as the name implies, have always been calls. That didn’t change because of the COVID-19 pandemic. And yet, the surge in mentions of muting started precisely in April and May, exactly when the pandemic took off in the United States. Was there a sudden switch from phone calls to Zoom calls, and with it a learning curve of how to mute oneself? But if that’s the case, surely people would learn over time and the incidence of being unexpectedly on mute would decline. That hasn’t happened.
I feel like there’s something obvious that I’m missing here. Somebody school me, please.