Sounds masterful. I've always explained Monopoly as a trading game unlike any other out there in that you spend the entire first 3/4 of the game building up to one big trade. It may be a complex multi-part trade, involving other trades in preparation, but it's all you were working towards. After that trade, you're just a passenger seeing how your valuations played out.
Sometimes, like what you did here, you can just structure everything so well that every trade is a better deal for the other player than it is for you, but the sum total of the trades makes you unstoppable. As I mentioned before, this is almost inevitable when you spread your trades between all of the players, and they don't trade with each other. So if you specifically target their needs (like you did), they might not even be able to come up with productive trades with each other...
Sometimes, like what you did here, you can just structure everything so well that every trade is a better deal for the other player than it is for you, but the sum total of the trades makes you unstoppable. As I mentioned before, this is almost inevitable when you spread your trades between all of the players, and they don't trade with each other. So if you specifically target their needs (like you did), they might not even be able to come up with productive trades with each other...