Leadership is responsibility.
If we see leadership from that perspective, we could agree that there is a severe shortage of good leadership in the world.
Leadership naturally confers responsibilities. But not all leaders take responsibility. Some leaders just like the perks of office, they never do their job. Some are strict professionals, they only do their job. Others go all out for the common good either it is part of the job description or not.
True leadership is taking responsibility.
Taking responsibility means 1) you handle your assigned tasks well 2) you take initiatives to ensure even tasks not assigned to you but would impact the overall goal are taken care of.
Being responsible is hard.
Taking responsibility is never in the past. I mean, you do not say because i used to be a responsible leader. The consequences of inaction or delayed actions are often grave.
Whoever knows how to take responsibility is a leader already, with or without a title or role. Half of the world's problems are caused by people not doing what ought to do and the other half is caused by people not taking responsibility to solve a problem because they felt "well, it's not my job".