Yes, but all of them being commodities (what I said) is not the same as inflation only being accurate when someone purchases every commodity available in the marketplace (what you said).
Inflation of a portfolio of iPhones is completely different than inflation that an average American pays due to cost of living changes in the economy. You're cherrypicking a hypothetical scenario that doesn't apply at all to the example at hand, which is the average person's ability to pay for emergencies that arise related to living expenses.
https://www.bls.gov/charts/consumer-price-index/consumer-pri...