Is the CPI accurate? When regarding the CPI, why is the selection of G&amp;S within it always favorable to what it has been for years? I ask because some economists and businessmen have seemed to find goods and services that have proved the CPI and inflation cohesion wrong. Are they fishing to deeply to find G&amp;S that is to abstract? Or is that they are opening a larger topic of discussion that no one wants to believe?
Price measurement in most national and international agencies is based on the “statistical approach” to price indexes developed by Dutot (1738), Carli (1764), and Jevons (1865). The methodologies developed in these papers form the foundation of 98% of all consumer price indexes generated by government statistical agencies (Stoevska, 2008). Following this approach, statistical agencies are more likely to select a good for inclusion in the sample with a past high sales share. Because agencies typically choose products based on their historic sales shares, this explains why "the selection of G&amp;S within the CPI is always favorable to what it has been for years".

Economic theory has largely rejected the "statistical approach" to price measurement in favor of the "economic approach," which asserts that all price indexes should be derived from consumer theory and correspond to the unit expenditure function. See Redding and Weinstein's paper "A Unified Approach to Estimating Demand and Welfare", they provide the argument and the above  references.