I liked the writeup. I definitely see how this principle of marginal advantage extends to any competitive game that I am aware of.

Spiritually I would compare it to the concept of ruin[1] in betting games. It doesn't make sense to bet your entire stack on a single event that is anything but a certainty. A smart better must always hedge their winning odds by retaining a small portion of their funds. Similarly, marginal advantage in a game should be considered as probability edge, rather than a guarantee.