There once was a game called Puzzle Pirates

The other thing that Puzzle Pirates had was a very complex and finely balanced economy. Players earned gold from sailing and completing missions as in Sea of Thieves; but they could also harvest raw materials and sell them to other players, who would use them to make clothes and weapons and cannonballs, and sell them in shops to yet other players. There was also person-to-person trade allowed, and you could gamble playing Poker, Hearts, and other games.

The commodity runs that you can now do in Sea of Thieves are somewhat reminscent of the sorts of voyages you would undertake in Puzzle Pirates.

It was hard to get very rich in Puzzle Pirates, although dedicated players could do so. But there were sufficient gold "sinks" in the game to balance out the ways in which you could earn gold. For example, black clothing required black dye, which could only be made from Kraken ink. Because Kraken ink was a rare commodity, it became very expensive, and so black dye, and black clothes, became expensive too; with all prices being set by supply and demand.

Sea of Thieves has too little in the way of money "sinks". The 200gp you spend on buying voyages was clearly intended to be that, but it is a pittance and there are now too many other ways to make gold without needing to buy a voyage (e.g. Forts, Fortresses, Skelly Ships, Random Loot, Ashen Winds, etc. etc. etc) Rare's only answer to this problem is 8,000,000gp ship parts for Pirate Legends, but they are optional, and simply serve to show you have -- or once had -- that sort of money to splash around.

I do not suggest Sea of Thieves tries to reproduce the complex economy of Puzzle Pirates. Despite the common theme, they are very different games. However, Sea of Thieves might benefit from more money sinks, and I would personally like to see gambling games introduced, it it were possible.