USA's focus on Afghanistan, Iraq, Libya and Syria has given China a fifteen year respite from conflict with USA to develop its economy and its military. This has been a good outcome of 9/11 which has saved the world from the prospect of a large conflict between China and USA.
How many people remember the incident of April 1, 2001 when a US spy plane was forced to land in China and the crew detained. This could have portended a period of intense conflict between USA and China but the issue was eliminated from the screens after 9/11.
In the meantime the USA was over-extended militarily and financially by 2 and more wars and spent $ 1 trillion on killing hundred thousand+ Muslims.
While this was happening China grew its economy, its military and its status. Even now USA is in no position to militarily challenge China because it is still engaged in interminable wars and has also decided to commit economic war on Russia.
In the current world political environment China can engage in the current domination of island acquisition in its own sphere of influence. Furthermore, the USA cannot be sure Russia will not join in if there is a conflict involving its neighbor and ally China.
http://nationalinterest.org/blog/the-buzz/why-9-11-spared-china-dangerous-duel-a... Quote:Take a step back for a moment. Before the shocking events of September 11, think back to the other big international event of 2001—that of the U.S.-China standoff during the Hainan Island incident. Relations between the two nations, clearly set to decline as they no longer shared a common foe in the Soviet Union, seemed destined for dark days. As Mr. Ching observed for The Diplomat magazine in 2011:
“Ten days after the crew was returned, Bush decided on a major arms deal for Taiwan. . . the biggest arms package since his father decided in 1992 to sell F-16s to Taiwan....
An article in the Washington Post on June 22, 2001, reported that ‘China’s leaders are increasingly concerned that Washington and Beijing are headed for a confrontation as China emerges as an economic and military power in Asia.’
“The article, citing both Chinese and US officials and analysts, reported concern that ‘shifts in attitudes in both nations seem to be pointing to a showdown.’...
With the United States already under attack, the Bush administration’s attention was no longer focused on China as the next enemy. Instead, it redirected its attention to radical Islam and Al Qaeda’s operations around the world. The fact is, it’s not going too far to say that China owes a huge debt of gratitude to Osama bin Laden.
After the September 11 attacks, the United States launched wars in Afghanistan and Iraq which, so far, have cost well over a trillion dollars and taken the lives of 6,000 US soldiers.