What makes a good cook?
From experience, it seems like people who are known as good in the kitchen just memorized the correct ways to prepare a number of dishes.
You toss new ingredients with different preparations, suddenly their food turns out as shitty as if it was prepared by a clueless idiot.
As obvious as it might sound, is this skill simple memorization? would a master pizzaiolo learn how to make sushi as fast and as good as someone with no experience, for example?
The impression I get is that someone can't be considered good a cooking, as this would be too broad. Calling them good at cooking certain specific recipes sounds more reasonable.
Some people have a deep understanding of what goes on when certain types of heat are applied to different chemicals, the way certain flavours interact, and the way these things effect the outcome of a dish. Would you not consider those people good cooks? Check out cookinginrussia on YouTube.
Technique and picture related.
Technique can come from both classical training and busting your ass and building experience, but a good palate comes only with experience.