Over the long run inflation is supposed to be zero

No they don’t; monetary policy determines the rate of inflation. 

OK, inflation is by definition a monetary phenomena, but it is illegal under the current system. All players are assumed economic, and the Fed sheet mostly balances.  That implies, if you are symmetric, that prices don't change over the long run.

Fortunately for us the convenient fiction allows us to force inflation at the last minute via bankruptcy.  Once prices begin to settle, events become impossible going forward and the Fed breaks its rule and accepts default.

This horrid fact is what induces Uncle Milt to recommend a deliberate loss of 2% each year by the central bank, and have the loss accumulate on its books.  In other words, why inflate every 50 years via government fraud when we can inflate yearly by government rule.