This is dumb on multiple levels. Consumption has nothing to do with how much money you make. A progressive income tax does account for that (to some degree)…A consumption tax fundamentally ignores it. Bill Gates could decide tomorrow that he’s going to retire fully and plant a garden in the backyard and never spend another cent outside of consumables…. The vast majority of his wealth would accumulate, untaxed. A single mom could do the same thing, but they would have zero wealth coming in as their minimum consumption ate up all of their wealth. The flat tax is dumb, always has been dumb, and will continue to be dumb in the future. It’s a possible scheme for the ultra wealthy who hoard wealth.
Inflation on its own is not a tax. Taxes are collected by our government. If Gasoline skyrockets because of a war in Ukraine and associated sanctions, that has nothing to do with the US’s tax policy, the US isn’t collecting any money on that, even though it might spike inflation (just as it did in real life)