Remember, it's the shareholders that pay these fines. And no one in the bank corporation is held accountable.
Shareholders own the company. If they want to hold the people who run the company accountable, they can.
That's the way business is done. Shareholders own a piece of the company, and they elect a Board of Directors who help represent their interests. The board then tasks the executive (CEO, etc) to to perform the day-to-day operations of the company in accordance with the shareholder's wishes.
If the company does something that earns a fine, the shareholders are vulnerable, because they own the company. If the shareholders feel this is causing the company to lose focus, they can pressure the board to change thing. Of course, shareholders have to balance the need for punishing those responsible with the value to the company - if despite the fines the company is better off the way things are, then it is in their interest to just eat the loss and go on with life because their value will be preserved.