Comment by JumpCrisscross

> GDP is just more people spending more money for more expensive things. It's kind of a failed metric for economic productivity

It's a good metric for a tax base.

> unless you think an $8 Big Mac is twice as productive to the economy than a $4 Big Mac

Which is why we consider both nominal and real GDP. (In your example, the former represents 2x nominal GDP. They're equivalent in terms of real GDP.)