Mao was actually quite close to losing power after the colossal failure of the Great Leap Forward. Although he remained Chairman of the CCP, he resigned as State Chairman and his successor in that seat, Liu Shaoqi, along with Deng Xiaoping, who were both very moderate, attempted to take measures to revitalize the economy.

Mao's government was criticized in conferences, but he managed to stay in power and regain it through the Cultural Revolution. The whole point of the CR was to purge the government and country of "bourgeois" capitalists and pretty much anyone who wasn't a pure Maoist. This was bad news for Deng and Liu, who were both purged from the government (Liu actually died while being imprisoned while Deng resigned all his posts and went away to a work camp). With Mao's great propaganda machine and pervasive cult of personality running the CR, he held onto power until his death.