More goods and services mean more wealth, because that is the definition of wealth. More goods and services compared to last year, means that the productivity has gone up. If this happens and nothing else changes, prices measured in money go down and the value of the money goes up, because that is the definition of value of money. So you don't need more money. You never need more money, a fixed supply is always enough.
If fixed supply is always enough then why inflate btc to 21M? Why not premine 21M and give everyone an equal amount? Let the people decide which money they prefer to use?
That could have been done (see Auroracoin). The mining is partly for initial distribution of coins.