>If an economic policy had bad outcomes because of bad luck, and the unlikely adverse event was appropriately considered as a possibility when the decision was initially made, then the sheer bad luck shouldn't count against the decision when we are retrospectively evaluating it.

No, you need to weigh the severity of bad outcome. If you play Russian roulette for 100M - you don't say "excellent opportunity - 5/6 chances I walk away with 100M". No ammount of money is worth that kind of risk to me.

Of course, that's basic.

Anyway, economic decision makers do do this kind of scenario analysis, where unlikely possibilities are considered, using for example SDGE.