Perhaps the problem lies in the dichotomy "buy insurance" versus "do not buy". It seems to me that you have, in fact, got three, not two, options:
a) Buy insurance from someone else
b) Spend the money
c) Save the money, in effect buying insurance from yourself.
I think option c) is showing up in your analysis as "do not buy insurance", which should be reserved for b). You are no doubt correct that Gates does not buy car insurance (unless perhaps he is forced to by law), but that does not mean he is not insured. In effect he is acting as his own insurer, pocketing the profit.
It seems to me, then, that Kelly is telling you that the richer you are, the more you should set aside for emergencies, which seems to make sense; but it cannot distinguish between self-insurance and buying an insurance policy.
So you say that if Kelly says to buy insurance for $300 if the insurance costs $100 I should not buy the police but set aside $300 in case of emergency?
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.