For one, grocery prices have risen by more than 5%. (My own experience is more like 30-40% just in the past year.) For two, grocery prices are one metric among many in the cost of living, e.g. you also have to account for housing prices, energy prices, etc. And, of course, wages are not rising commensurate with the overall CoL, they have been essentially flat for decades.

So while your math is good, it's not meaningful. I find it very weird the lengths people will go to in trying to make one-off metrics reflect a different reality than what is very clear from people's experiences.