> Or, here's an idea, maybe we should use a weighted index of several of those things as a measure

That's done already. More useful: such index as a ratio of wages. Say, [price of standardized basket of commodities] / minimum wage.

That would tell you how many # of paid work needed to (for example) fill a shopping cart with a week's worth of food + heating / powering one's home over that time.

("minimum wage" = applies to folks scraping by in low-paid jobs. Higher earners are living the good life anyway, imho).