What this analysis reveals is that the growth of Chinese power under one-party rule has peaked. The seductive authoritarian state-capitalist development model may have delivered an economic miracle in the post-Tiananmen era, but for all practical purposes this model has lost its magic, if it has not gone totally bankrupt. However, China's future does not have to be a dismal one. The obverse of this analysis is that, with the right reforms, particularly a return to a pro-market growth strategy and a transition to democratic rule, China can comfortably confront these domestic and external challenges.
China's growth could still lead it to pass us in GDP, but we could regain that title by the end of the century, I think.
Of course, the danger is that rather than a (relatively) declining power--America--resisting a rising power--China, results in war during the power transition as we fail to accept our new role; that a war could result from China believing they must strike at their peak before their relative decline allows America to again pull away in the power equations.
China could end their crony capitalism and government control of their economy and society to renew their growth potential.
You'd think a country renowned for long-range planning could see that they need to make this transition rather than cling to power.
Or we could just screw up our country for good by becoming a European social democracy. Some people here want that, after all--and think it represents the culmination of long-range thinking.