Actually, this is the opposite of a one-world order.
This is a Third World sh!t-hole telling the one-world order that they prefer a Third World sh!t-hole to a one-world order.
For what it's worth ... there are 23 U.S. states (individually) whose GDP exceeds that of Greece. Eight of those states have a GDP that is at least twice the GDP of Greece.
Your point is well taken. Greece has a very small economy and the Europeans should be able to insulate themselves from a default. Greece's three main industries are agriculture, tourism, and shipping. When Greece exits the Euro and begins to print its own currency, which will probably immediately start to devalue, it will help strengthen all these industries.
In the long run, a divorce will help both parties. In the short run, there will be some pain for both.