Keep in mind here that I don't claim to be expert. in fact I so rarely articulate any of this that I find it beneficial to "spar" with you. Very few topics I dare take expert stance on.

One quick thought is that such a measure can't be done. No way to measure unchanging purchasing power of every individual over time. Best leave pricing to free market. And I just don't see how some arbitrary external decay rule guides the free market system better.

I'll think about it more maybe. Thanks for the insights