Actually, you really don't get it.
The financial system is fundamentally held together by one thing: trust. The US Dollar isn't the key currency because the US was the largest economy, or because we have the most weapons - although those things factor into it. The US Dollar is where it is because the US has the political will and ability to support the world financial system when things go bad, even though those actions may cause severe short-term problems in its own economy.
Do you trust China to manage your currency? Even the Chinese don't trust their government when it comes to money. Russia? The EU?
Good luck with that.