of course they did, the penalty for getting caught destroying evidence is far, far less than the penalty for the price fixing they’re accused of. the law is designed to incentivize them to do this.
we could make it so that the penalty for destroying evidence in a court case once its been subpoenaed is twice the penalty of the original case, but we don’t. we could make CEOs responsible for the actions of their employees (after all, they’re quick to claim responsibility for the actions of their employees when those actions generate money), but we don’t.