As much as the notion of "Purchasing Power" is <macro>economic, thus perhaps having a greater chance of being related to reality, I've been wondering if - and how - could these long-term measures account for greater diversity and "scale" of "things money can buy".

Nowadays if you're properly rich you can buy a seat on a sub-orbital flight. This wasn't an option in '00, no matter how rich you were.

On the other end of the scale, for basic things a (really) good quality loaf of bread will always be cheaper in Poland than say up north from Oslo, Norway; whereas a USA-designed made-in-China laptop pretty much never did scale with the rest of the "CPI basket"...

Point being: we sure do have numbers - what they really mean in practice is vague at best.