The nation cannot consist of "indespensible leader[s]". For one leader there has to be many regular people/followers. Same way as no army can/should expect every soldier to be a general.
Once again you got me on my poor use of the language. The concept I was trying for was to be at least important enough that you could safely make it the next ten years without being laid off or seeing your job or project shipped to others. The latter needs a little skill at determining what management has in the works. But someone with all those years of experience behind them should be in that position, or should have at least indebted the company sufficiently that they will find a job for you somewhere. In addition by this time one should also have a goodly amount of cash invested to lead into a certain level of retirement.