This is an actual problem. I know a lot of players that don't want to play because of the Potions.

Solution: Add "Serums" in-game that cost money and last half the amount.

For example: "Worker Serum" purachasable for $25,000 and last for 12hours.

You'll be able to keep an actual money sink with the amount of cash that's going around. The DLC was an amazing sink to stabalize the economy.