A billion here, a billion there

UBS has been hit with $1.5 billion in fines by the US and UK for manipulating interbank rates since the 21st century began.  But, again, no one from senior management will be penalized by spending a little time in jail.  A couple of traders may serve time, but not the guys who made these crimes happen.  All fines paid come from the company, not senior management.  Why should they not repeat their crimes or create new ways of robbing?