My understanding is the following: In companies, it is assumed that employees will try to reach for the promotion, getting a higher position for a higher pay. Managers have been trained to use that to push people to do more than what is strictly required of them, letting people think that's how they'll progress their career. Quiet quitter are people that simply stopped aiming for the promotion, they do what their job entail and that's it, no more trying to get more, no extra, no internal politics. They don'tgive a fuck about all this, all they wantis the paycheck and to enjoy their life away from all this non-sense.

They pinned the term quiet quitter, because this is usually the behavior of an employee that is about to quit the company for another position elsewhere, except quiet quitter don't plan on quitting.