I've seen that kind of thing happen.

My own heads of department wouldn't have the power in this economy to blacklist anyone in matter how bad because they just need bodies to fill seats. We currently have people who don't know their alphabet or have stalked their bosses back working.

However even now there are people who are perfected good at what they do but can't get a job because a star didn't like them for some reason. Those famous people have huge influence across studios and other stats, they all pull together, whether the star themselves is liked or not.

It's a matter of hierarchy. The studios might not like Gibson but they will always like him more than you and me. If he says you're shit they will agree and pass it on. This is how Weinstein operated. Everyone hated him and he had no say at the big studios but if he said not to work with someone they went along with it because he was one of them. Peter Jackson was turning down people for Lord of the Rings and he didn't know why. He just knew it was the received wisdom not to work with them. Of course it was because they'd turned Weinstein down for sex.