Inflation, especially at the time horizons the article is looking at, is a monetary phenomenon. Younger people entering prime spending years has nothing to do with the systematic inflation rate.
“Too many dollars chasing too few goods” = inflation.
Beat me to it. Never ceases to trouble me how fundamentally ignorant people in the media are about this basic fact of economics. Expansion of money supply above and beyond increases in productivity is inflation. Everything else is just consequences.