END GAME: Frustration and despair
At this point, you more or less have the game sewn up. If losing a normal game of monopoly is frustrating, losing to this strategy is excruciating, as a losing opponent essentially has no path to victory, even with lucky rolls. Your goal is to play conservatively, lock up more resources, and let the other players lose by attrition. If you want to see these people again, I recommend not gloating, but simply state that you’re playing to win, and that it wasn’t your idea to play Monopoly in the first place.