No. The headline Consumer Price Index does not swap one product for another when prices change, and that methodology did not change after COVID. The substitution idea is real, but it lives in a different measure: the Personal Consumption Expenditures index, or PCE. PCE is built to capture the fact that when steak gets expensive, people buy more chicken, so it reflects the mix of things people actually purchase as that mix shifts. That design is why the Federal Reserve treats PCE, rather than CPI, as its preferred inflation gauge. The common criticism of PCE is that substitution understates the sting of rising prices, since the index assumes people trade down. Both measures get published side by side, and neither was rigged by a recent rule change. Why a homebuyer should care: the Fed reacts to PCE, and the Fed's read on inflation is one of the biggest forces on the direction of mortgage rates. Knowing which number the Fed actually watches helps you make sense of the rate headlines instead of getting whipsawed by them.