Prices do, in fact, go down. For example, eggs in the USA went down from $6 to $2 in the past few months. https://www.macrotrends.net/3052/us-egg-prices

Long term average? Sure, it goes up, that's inflation. But do you know what causes inflationary pressure? Visa and MasterCard adding unjustified fees because they're a duopoly and control most of the payments market, and your government won't regulate them and cap fees.

The UK and the EU both cap debit card fees at 0.2% and credit card fees at 0.3%. When the UK left the EU, Visa and Mastercard jacked up their fees over 5x for UK-EEA payments. Not because they had to, but because they could, and they love sucking money out of other peoples' businesses. https://www.psr.org.uk/our-work/market-reviews/market-review...

Retailers in competitive industries absolutely do use a reduction in card fees to lower their prices. Maybe not all the way, but they definitely don't give it all to themselves as margin; their competitors don't.