"Operationally, the PLA and U.S. military have very different needs. The U.S. is geographically isolated from its foes and instead depends on a massive network of overseas bases on six continents to engage or contain adversaries. This requires globe-spanning logistical capabilities including hundreds of transport planes, aerial refueling tankers to keep jet fighters and transports aloft, and amphibious transports and carriers to convey Marine units. Just as importantly, strong diplomatic alliances are necessary to maintain those overseas bases and keep them supplied with fuel, personnel and munitions. For example, U.S. operations in Asia are heavily dependent on alliances with South Korea, Japan, Singapore, the Philippines and more recently, India. Several of these Asian countries, as well as western and central Europe, also rely upon U.S. military forces to meet their security needs.
China is only beginning to acquire such logistics and is situated in a very crowded neighborhood surrounded by potential military competitors such as India, Russia and Japan. (Personally, this author does not believe contemporary Japan will become an aggressive military power anytime soon, but the Chinese don't see it that way due to their bitter memories of Japanese invasion.) Additionally, Beijing has only a few military alliances with Pakistan, North Korea, and a few southeast Asian nations. But, China is slowly developing multi-national institutions such as the Shanghai Cooperation Organization and its aspirational Silk Road project in hopes of fostering stronger ties."
