> It's not valid though. Inflation driven substitution means lower quality.
It really is valid. Not only is it valid, it's precisely the whole point of tracking a consumer price index. The goal of CPI is to track the prices of goods and services consumed by the population, not brand- or product-loyalty. When prices go significantly up, it's a known fact that consumers react by seeking affordable alternatives, or in the case of luxury items simply going without.
It really is valid. Not only is it valid, it's precisely the whole point of tracking a consumer price index. The goal of CPI is to track the prices of goods and services consumed by the population, not brand- or product-loyalty. When prices go significantly up, it's a known fact that consumers react by seeking affordable alternatives, or in the case of luxury items simply going without.