I don't think this is the right way to look at it after you exit. At that point there is no more risk, so that should be compared directly to the opportunity co

I don't think this is the right way to look at it after you exit. At that point there is no more risk, so that should be compared directly to the opportunity cost (if you're the entrepreneur at least). If you're the VC, making exactly the expectation value (risk*reward) isn't a success, but it's hardly a failure as long as it's beating market rates...