I'd go further: a bad manager can turn a great engineer into a very bad one. People look up to great people, and when the strongest performers are demotivated, that spreads.
Commonly in the cultures that end up this way, leadership blames / gaslights the ICs. It's toxic and honestly kind of heartbreaking.
If they are very bad, the company can let them go. If they are simple good or fine, the company lost their great engineer, and now has a seat filler that they can’t justify firing.