No.

What disincentivizes future whistleblowing is the prospect of never being able to work in your field ever again, because your boss, or rather his boss, talked to his counterpart at the other aerospace companies, so now no one will hire you.

You then drown in debt, and die penniless on the street, years or decades later. Depending on your luck.

Simply killing someone is messy. You might get caught. Ruining a man's life to the point where he kills himself? That's disturbingly easy.

Again, the lawsuit was not over John Barnett's whistleblowing. That case had concluded a few years earlier, with Boeing being found in violation of some safety standards. They got a fine and John Barnett got fired. Except Boeing didn't "Fire" him, they forced him to retire.

So John Barnett sues Boeing for wrongful termination, and loses. Boeing has some very expensive lawyers.

John appeals the loss, and that's what this court case was about. He was giving testimony about how Boeing retaliated against him. And he obviously thought that he was going to lose again.