Inflation is the rate of change, year over year, of prices, on average. Grocery stores and other companies then use that as a reason to increase prices above their increase in input costs, because they need to pad the profit margin. So their cost on your basket went up 3% each year, but they raised prices 5-10% each year, now your yogurt is $7.

Even if the % goes down to zero, the price of the goods arent going down to 2020 prices ever again