There's plenty of space to hide reality when building a price index.
Price index do not capture the reality of most people cost of living. They don't capture the family that have to buy margarine instead of butter, because butter became too expensive, while margarine became cheaper, Weight both items as the same, and voilá! no inflation, increases in the price of butter were cancelled by cheaper margarine, fuck you if you prefer butter.
We can also do the same with housing: Capture prices as the average of a basket of cities. In reality, some cities will have absurd price increases while others are in decadence. The average prices increase of a disputed locality like NYC metro area will probably be masked by the fact that houses in BeltRustAssEnd, MI are becoming increasingly cheap. But, for the real person, what the fuck matters if BeltRustAssEnd houses are cheap as bananas? Who can get a job there?
And of course, a single number cannot capture the subtleties of reality like the fact that while it is great that 80" TVs are now so cheap that they can be bought by the commoner, this fact means fucking nothing if having a roof over your head in a place where you don't need to spend most of your live commuting is becoming increasingly too expensive for a lot of the same folks. Too bad the commoner is just a paycheck away from being in the streets as he cannot pay for a house! He now has a TV that not even Queen Elisabeth could have just a few years ago!