I asked chatGPT:

If a player runs out of Bitcoin during a game of Monopoly played with Bitcoin as the currency and there is no option to borrow or earn more Bitcoin, then the game would become more challenging for that player. They would need to rely on trades with other players or on lucky rolls of the dice to generate income and stay in the game.

In a Monopoly game with traditional currency, it is possible for the bank to print more money, which can help players who have run out of cash. However, since Bitcoin has a fixed supply, this option is not available.

Overall, the limited supply of Bitcoin would make the game more realistic and challenging, as it reflects the scarcity of resources in the real world. Players would need to be strategic and careful with their spending in order to succeed in the game.