Not trying to be difficult, but you're not really addressing my question.

Why can't you address this with mitigants I mentioned? It sounds like you do some of that with "other non-$ comp" (mandatory PTO, parental leave,...) that's use it or lose it, but those are table stakes these days.

I love the idea of thinking about a long term marriage and contracting accordingly, but at some point it's a leap of faith.

Your bias has a presumably unforced handicap. Losing that 100x programmer may not matter to your business/personal goals to make GOOD wealth accumulation, but it will hurt your changes to go from GOOD to GREAT outcomes.