So it occurs to me that without a bit of term-grounding, people might think I'm making somewhat contradictory claims. I'm saying: "It's not great for the III Initiative folks to connect playtime directly to quality" but then also saying: "III to me implies a high level of polish." So I want to clarify that when I say 'polish' and 'quality' I mean different things.
Quality is a subjective value judgement of how good something is. It is, of course, inextricably linked to what we think the purpose of that thing is. Your values about what games are for and what games should be inform what you think a game's quality is.
Fidelity, usually graphical fidelity, is a descriptor for how well a game disguises the underlying technical realities of how it makes images (sprites, meshes, etc) and successfully evokes an aesthetic. Typically we say this about games that adopt a photorealistic aesthetic; the less a game looks like a video game and the more it looks like something else, the more the fidelity. In a sense, 'fidelity' is used in the sense of reproduction; a game's ability to reproduce the look of a photographic image is fidelity. But this can also apply to aesthetics other than photorealism. The Guilty Gear games, for example, aim for a high degree of graphical fidelity in reproducing cel animation aesthetic.
Polish is more an evaluation of just resources and effort. Attention to detail. A game has high polish if environments in it are detailed and different from one another, if the UI functions smoothly, if it runs consistently on the hardware it's designed for, if players are unlikely to encounter bugs, etc. Polish is a set of technical evaluations divorced from an evaluation of quality; it just implies that attention was paid. Polish is a necessary component of achieving fidelity; I think most people in most cases would also say that polish is necessary for quality. But polish isn't quality. You can, after all, polish a turd (Hyneman 2008). An example of a high-polish, low-quality game is something like Detroit: Become Human.
