The economy is most basically randomizing of energy and so cost inflationary as energy is a must and a given in any economy save a basic barter one.  Also, being utterly embedded in the temporal universe, it refuses to/cannot possibly stand still in Time and so, in and of itself must flow in this cost inflationary state.  As this inherent costliness is additional to all other costs and it exceeds even the possibility of individual incomes equaling all costs (which of course except under extreme conditions never occurs either) it is necessary to implement the right policies at the right places and times in the process of production which is the economy.