I imagine that prosecutors don’t pierce the corporate veil for public companies often because “DA charges 87 year old grandmother with stake in Evil Corp in her pension fund with manslaughter, local union members brace for additional charges against members” doesn’t make for good headlines or good justice either.

The officers and board of the company aren’t protected by the corporate veil concerning their actions. They retain some degree of protection from actions of others within the corporation provided they did not have (or did not have a reason to suspect) knowledge of those activities. But to my knowledge that’s not special to officers, it applies to any employee which is why the rank and file Enron employees didn’t get prosecuted.

> You can prosecute and imprison officers and/or the board.

Right, that's just normal individual criminal prosecution; it doesn't require prosecuting the corporation.

Of course, it's possible for the corporation to be guilty of a crime without any individual officer or board member being guilty.

> A corporation isn’t a magical immunity shield for them - for some reason prosecutors have shied away from piercing the corporate veil.

Piercing the corporate veil is holding shareholders liable for certain debts (including criminal or civil judgements) of the corporation. It has nothing directly to do with criminal prosecution of corporate officers or board members for crimes committed in the context of the corporation (though there are certainly cases where both things are relevant to the same circumstances.)