You are on HN, the chance you are part of the american average is very low.
That 15% cost is not relevant if you don't drink milk. Its also a lot less if you are able to save money. That money saved might be for something very specific like one specific car or a house.
The house market, as far as i understand it, is more decoupled from inflation than not. Here in germany a farm costs still 600k and goes up and down based on location and other factors. My money in the bank doesn't has to be inflation neutral, it should be house market neutral for the money i only want to buy a house for.
You can also choose and change your buying power. Instead of the sports car x, you can buy y. Instead of buying the city center house, you can buy the farm outside.