So it seems bitcoin has an upkeep cost and gold does not, when it comes to maintaining the value the same. And if that upkeep cost isn't paid (in bitcoin's case) then you get a gradually eroding price.
I think you are mistaken.
Mining gold also has costs. The gold mining corporation must pay for these costs (equipment suppliers, employees, electricity, fuel, etc) with fiat currency. This means that the gold mining corporation must dump their mined gold onto the market to cover their costs. If this gold mining "upkeep cost" isn't paid with an equivalent amount of gold demand at the current gold exchange rate then gold gets a gradually eroding price.
This is simple economics. It's true of gold, corn, pork, bitcoins, or any other valued commodity. There is always a cost associated with producing the commodity. If demand is higher than the supply, then the exchange rate increases. If demand is lower than the supply, then the exchange rate decreases.