Well, games tend to have incredibly low barriers to economic entry and little in the way of maintenance or upkeep. Warcraft starts you out with five peons and a gold mine, right at your doorstep. Sim City starts you with abundant lucrative-to-develop free real estate and a bunch of low-interest loans, then extracts wealth continuously from the native terrain more-or-less indefinitely. Civilization and Age of Empires plop you down into a resource rich wilderness. Everything on the Monopoly board starts out as vacant, profitable, and for-sale.

Then the conflict is primarily between Player Commanders (or AI-controlled NPC Commanders). You're rarely struggling to "beat the board" or wrangle the restive unit tokens from whom you're trying to extract wealth. Your big threats are always adjacent and external. Nobody in Warcraft ever experiences a coup because their pig-farms pull in a bad harvest. But also, nobody plays these games once the board's resource pools have been exhausted. The game resolves. The End of History is reached. You win or you lose and then you start back from scratch again.

One of the "realistic" aspects of Paradox Games (and other historical 4X games) is that there is often an internal domestic struggle within your own board position. The games tend to be long and develop out over iterative cycles. Maxing out the board space comes relatively early and precipitates a higher degree of tension rather than a resolution. And players do eventually have to wrangle with soft ceilings on materials and manpower, the social ramifications of random historical changes, the politics of succession, etc.

Capitalism works great when history can just end and declare you the winner. Capitalism doesn't work when you're forced to keep talking about next cycle.