Thanks for the feedback. I think you’re right that a key omission here is failing to note that each step must be useful in itself, and provide a non-negligable boost to chances of survival on its own. It also implies a greater sense of purpose than exists in nature (there’s no mind aiming for things, just more resilient creatures surviving).
I realise the model has many flaws and omits wider context such as competition, but I’m still tempted by the appeal of using such a common situation as the analogy. Talk of guessing passwords or rolling dice does make excellent analogies, but if you want to engage someone it helps to talk about something closer to their personal experience, and I imagine most people played hangman on a board or margin at some point at school.