It is a game played by the American government so the economy seems better than it really is. Another example is that large part of the GDP growth in the US is related to health care, so you get here a double effect: higher economy growth compared to other countries with socialized medicine, and lower inflation numbers when in fact it is the opposite.

The Fed and the government in general are incentivized to make inflation appear much lower than it actually is. If you use the same calculation the Fed used in the 80s to measure inflation then we’d be at 10% today.