Staying on the Cutting Edge. It is true of leaders today, but it has been true throughout all of history. Some leaders keep expanding, making a contribution into old age, while others make the 'Great Compromise,' settling into a comfortable mediocrity. They might retain their leadership 'position' but they no longer serve as true leaders.
Some leaders lose their punch because they finally got the leadership spot they've always wanted.
They've arrived, so they quit working. It may have been a lifetime goal being elected to a certain office or getting a particular church. These leaders work like crazy while they are 'on the way up,' but when they get what they want they quit hustling. In fact, that's one of the reasons he got his current spot - people thought he would actually do the things he always talked about. But he didn't.