Your prediction on SPY hitting 320 assumes Bernoulli distribution, nobody knows where the future lies in the possible parallel universe cone. I would bet more like fatter tail Gaussian: Gaussian + power law. Personally i am not concerned about Gaussian outcomes much as my index portfolio is likely to be sufficient, as a big Taleb fan, avoiding left tail risk and (much less) exposure to upside tail are what I thought more about.
Your prediction on SPY hitting 320 assumes Bernoulli distribution, nobody knows where the future lies in the possible parallel universe cone. I would bet more like fatter tail Gaussian: Gaussian + power law. Personally i am not concerned about Gaussian outcomes much as my index portfolio is likely to be sufficient, as a big Taleb fan, avoiding left tail risk and (much less) exposure to upside tail are what I thought more about.