Basic microeconomics teaches that demand is a schedule of what customers are willing to pay at various price points, and that businesses need to apply "marginal

Basic microeconomics teaches that demand is a schedule of what customers are willing to pay at various price points, and that businesses need to apply "marginal" analysis aka calculus to optimize profit. There is nothing about the basic building blocks of microeconomics that makes it incompatible for the analysis of luxury products. Most product are not luxury products and a large portion of the world lives in poverty, so naturally most Econ 101 discussions of microeconomics will deal with commodity products e.g. bread. Like anything worth learning, it is far more important to understand the basic principles of the subject than to learn details about specific applications. That is memorization over understanding.