Agreed, I think the Single-I, Double-I, Triple-I tiers do a good job of illustrating the different budget and resources available to differently sized indie developers while still properly classifying them as "indie" because they still have full creative control and the power to set their own goals and timelines with no external strings attached to put pressure on it by investors and shareholders who don't give a fuck about anything other than money. Sometimes Triple-A developers can act with a high level of independence too, but it's always conditional and subject to change because those strings are there and they can be pulled at any time. With indie developers, that creative and developmental freedom is structurally explicit. At least until they sell out (but that's when we stop calling them indie).

Stardew Valley is an indie game with a publisher. It is not about publishing.