They're wasted potential. Burnout isn't necessarily from overwork, it comes from pouring your heart and soul into things that you never get the satisfaction of seeing completed.
Burnout is not from failing to complete things. Most work never truly "succeeds". It comes from trying hard to do good work, and having it sabotaged, prevented, micromanaged, and even punished etc...
Being denied satisfaction is the important part but yeah, there are countless circumstances that can result in it. Having to waste all your time fighting for limited resources because a handful of individuals are hoarding them is by far the most common.
In the US the so called "free market" was intended to be a way for people to achieve financial independence in spite of any persecution. Unfortunately regulatory capture has made it exceedingly difficult.