Is it? Can’t game it much or for long without being obvious because it’s compounding. Let’s say inflation is understated by 4% absolute per year. Over 40 years, that’s a factor of 4.
Fuel would be hard to game. It’s just fuel. Other components are trickier to calculate, like aggregate food prices or things involving hedonic regression. If there is gaming, you’d have to look at the tricky parts.
Well if you don’t think we’ve gamed fuel but do think we’ve gamed CPI significantly (ie several percentage points per year for decades), then we have made REMARKABLE progress in reducing fuel costs over the last 40 years, with fuel efficiency improvements on top of that.
https://inflationdata.com/articles/inflation-adjusted-prices...
Is the fuel cost per mile traveled 4 times higher than it was in 1981? No. Fuel prices adjusted for CPI are about identical with what they were in 1981 ($3.80/gallon): https://inflationdata.com/articles/inflation-adjusted-prices... And fuel efficiency has improved by about 40% in that time: https://www.epa.gov/automotive-trends/highlights-automotive-... (Even as vehicle reliability and safety and comfort have also gone up.)