Burnout is more than just stress overload. A lot of it has to do with long term attempts to force ourselves to be something else/do more than we can handle in the long term. But the feeling to burnout is very different than stress overload.
It's waking up feeling trapped... It's you forcing yourself to put foot in front of foot... it's you walking to the gallows, surviving it with no energy and no hope... Everything else in life fades. Your life becomes empty... no energy and no will to do anything. You'll hide yourself away in some corner, try to escape it, but it sits in your mind. The escape fades as soon as you stop doing it. You avoid bed, just because you know you have to get up... and every day ends the same... back in bed, unable to sleep, thinking about doing this again tomorrow. And the day after.
Soon the incremental stress takes it toll. Now the escape is going to bed. Depression sets in... you sleep as soon as you get home... and wake up and lie in bed for most of the night. The anxiety builds up... you start to become erratic. The body gets weaker... and the physical symptoms set in. You start taking OTC medications for headaches, tension, muscles. You see a doctor, get anti depressants, sleep aids... but that just raises your ability to function - raises the amount of stress your body will take before more functions start to break down.
Hmmm, sounds kind of dramatic when I put it that way. Anyway, it's the compounded amounts of small but significant stress that leads to burnout. Test "burn out", spurts of high pressure and stress leads to crashing and breakdowns... Students do get it, especially over achievers... but that's over the long run too, when they never really stop. It's harder for students to get it... less identity and fixed time lines break up the stress. And being trapped in a job tends to mean mortgage and family, never mind social pressures in general... that's a serious amount of long term (ie: 30+years) pressure to stay miserable.