Personally I think it's less about how much energy is put into maintaining your position, and more about how the system adapts to the presence of an individual.

Personally I think it's less about how much energy is put into maintaining your position, and more about how the system adapts to the presence of an individual. When an individual is in power for an extended period of time, the system adapts to them being there. The longer they're there, the more the system comes to rely on them being there instead of an arbitrary person being in that position. This, I think, is one of the reasons that the transition period in long running monarchies is so dangerous. All of the plans that relied on the specific qualities of the former leader just went out the window.