Great anecdote, but burnout generally isn't caused by that for most people. At its core, it's because of stress. Incompetent coworkers and organizations may certainly cause stress, but rarely is it so bad that it causes burnout.
The ambitious people who take 500k/year jobs at HFT firms are to top .25% of "workers" in some abstract measure, and have different expectations and causes of burnout relative to the median burnout experiencer who is for example a school teacher or administrative assistant in an office job. Some people have an addiction to the fast pace, feeling of being need, and stress.
Loss of efficiency/productivity might not be the product of burnout. It might be the cause.
People get addicted to the dopamine hits of getting things done and when they hit a wall, enter a vicious cycle of depressive withdrawal. Recovering from burnout by taking a break is simply resetting that dopamine addiction. Just a personal theory.
If you work in a high paced environment with competent colleagues, management and tooling, you can just keep rolling with the punches and never hit the wall.
https://www.mayoclinic.org/healthy-lifestyle/adult-health/in... https://www.helpguide.org/articles/stress/burnout-prevention...