Total Money should somewhat reflect the total wealth of the game world.
As long as a game is generating wealth (items, etc.) all the time, also the amount of money should grow, to keep a balance between amount of money, and value of money.
If you increase the wealth of the world only, without increasing the amount of money, each unit of money would get worth more in real life. But not in game worlds with fixed prices. You'll end with a very odd situation where there is big wealth in items, but it's not affordable, because the amount of money is too small, and the value of the money too low.