Efficient systems are brittle systems. You wring all the slack out of it and any shock is going to cause failure. In this case, the slack is the nurses and other healthcare workers' mental health and burnout limits and pay and culture etc. etc. The slack is being pulled to lower costs and increase insurance/hospital profits.

It's unsurprising that what has happened in the past couple of years is putting stress on a system with the slack pulled out of it.