Comment by Retric
Tax brackets also shift through time, though less frequently. So if you only get COL increases for 20 years you’re going to be reasonably close to the same after tax income barring significant changes to the tax code.
In the US the bottom tax brackets where 10% under 2020 $19,750 then 12% next bucket, in 2025 it’s 10% under $23,850 then 12% next bracket. https://taxfoundation.org/data/all/federal/historical-income...
And here I am in the UK, where the brackets have been frozen until 2028 (if they don't invent some reason to freeze further).