This is especially true with my previous employer. Managers are always adding workload to employees. And when people leave, they put the work on other people. What keeps happening is high turnaround because people cannot take it anymore, and they are able to find better jobs because of the additional work experience they inherited. And when they leave, things get worse because the loss is even bigger.
This happened to me so many times, so I've picked up so many things outside of my work, and eventually was able to find a better job that doubles the pay. Many interviewers were surprised by the amount of things I was able to accomplish and quite frankly, I was a little surprised too.
My wife, my cousin, my high school friend, and me all got new jobs with better pay and less stress in the past few months. So when I see employers complaining labor shortage, I laugh.