Part of the reason stems from the absence of any mechanism for “the world” to come together. The United Nations General Assembly comes closest, but little can be expected from an organization that equates the United States or China with, say, Fiji or Guinea-Bissau.
部分原因在于没有任何制度将“世界”拧在一起。联合国大会是最接近的制度，但在联大，美国和中国与斐济和几内亚比绍平起平坐，对于如此组织，你也无法提起多少期望。