USG cannot conjure value out of thin air, so any "free" returns must come from changing the unit of measure. The no-risk USD instrument with the highest rate of return is where conservative money should generally end up, and thus its return is the expected monetary base expansion. And since this expansion is distributed evenly across the economy, by definition it's inflation.

When analyzing inflation in terms of prices, one must also take into account how much those prices would have otherwise dropped due to non-monetary factors such as technological and market progress. If a certain widget is 10% easier to produce than yesterday but the price remains the same due to monetary base expansion, that's a silent 10% reduction of what today's purchasing power should have been. With exponential technological progress, this term is ever-more important.