How would you calculate the theoretical average time between each successive "World's Oldest Person" dying?

There is no theoretical formula, but you could come up with a statistical formula. It would need to be based on knowledge about the world's oldest people, and the only way to get that knowledge is by studying historical data. The most direct answer to your question is that you can't, because there is none.

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I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.