Conjecture

SYNTHESIS: a health plan with high member turnover is Diamond's roving bandit, and the measure that separates the two kinds of bandit is the ratio of the decider's tenure to the latency of the harm. From Diamond: failure follows when "the principal consumer has no long-term stake in preserving the resource, but society as a whole does"; loggers on short leases "have correctly perceived that, once they have paid for their lease, their interests are best served by cutting its forest as quickly as possible", while a company that owns the land and "anticipates repeated harvests" may find a long-term perspective "to be in its interests". From ours (C-Z1H9GJ1307): outcome payment reaches prevention only when the party paid holds the person longer than the disease takes to show. Together: below a ratio of one, a rational manager of a forest, a body or a planet draws the stock down; above one, the same manager conserves it for selfish reasons, which is enough and needs no virtue. Ord's existential risk is the limiting case, a harm whose latency spans every future generation, so no member's tenure can cover it and the stake has to be held by an institution built to outlive its members.

Paying for health, not sickness