After Mao died, the social and physical devastation wrought by his Cultural Revolution still fresh in everyone's mind, the Communist Party leadership reorganized itself with the deliberate design to prevent another cult of personality from emerging. Power was decentralized and a system of checks and balances set in place; in particular, leaders would rotate into and out of the highest offices, and not hold more than one senior office at a time. This was a largely informal system but in reality taken far more seriously than any written law.

IIRC (I'm just an occasional observer), this system broke down with Hu Jintao, Jingping's predecessor. Both men held all three senior positions concurrently. Jintao didn't have the clout to hold onto the reigns, but it's unsurprising that Xi Jingping has done so.

In any event, my point is that until recently it was impossible for any singular political figure to have as much political or social influence as Xi Jingping. Xi Jingping's rise to power is the result of what is effectively a constitutional shift (regression?) in the structure of political power in China.