Hate to go off topic here. But doing ones job is not the only criteria based on which Chinese leaders are selected. There is a elaborate system of patronages, favors, groupings, mentors & back room deals, which are the actual deciders in people landing top jobs.
Take Xi Jingping for example. He belongs to the Jiang faction in the politburo, though Hu wanted to push his own man Li Yuanchao (current head of the Organization Department) to the post of party secretary but he could not succeed as the politburo mostly contains Jiang loyalists. All this struggle behind the scenes is the reason why Xi was appointed a year late in the position as deputy chairman of the CMC. Presumably there was an understanding reached between the Hu and Jiang faction that Xi will not trample upon the interests of the faction lead by Hu Jiantao in the CPC after taking over as party secretary.