If you compared to how CPI and RPI compare (calculated geometrically vāv arithmetically), then CPI probably is a more accurate reflection of living costs (certainly, for pensioners). The problem is with how it was introduced and applied (retrospectively). As everyone advanced their careers, and if everyone knew (in pension fund accrual, notional pot or otherwise) what the future was going to be like, it may have been the case that pay would have increased more to compensate. I have no real issue with RPI in isolation, but I do have an issue with how it has been applied in context.