It takes a special kind of stupid to believe a coworker/employee is incompetent and still push all work onto them. Those are also mutually exclusive. Either the person is actually unable to do the work at all and all you get is bad quality products that ultimately won't sell at all, putting your company at risk. Or the person does a good job and delivers good products but then you have to admit their competency.
This is probably a meta comment about jp black companies where everyone is being yelled at for doing sub par work, yet guilt tripped into staying until they die of exhaustion, I guess.
Yeah, the common underlying theme is nearly always "leaving a black company and getting rewarded for your skills" (Maaaan, what a good power fantasy! My personal favourite was the Demon Lord one where salaryman was ejected from a JP company, isekai'd, and one of the first things the Demon Lord says is "I read your CV, and I was very impressed!" 🥰 ), but, very often, it's either ignorance or, as mentioned, that special kind of stupid.
But another common thread is that they've had this good worker so damn long, who at least
partly got their skills precisely
because they were put through punishing conditions, that they genuinely don't recognise their worth. Not helped by the fact that usually, the boss hasn't
worked a day in his life since they got to middle management.
...Looking back, none of them have. And they're going to have the usual
very rough awakening.