To get that outcome, you probably need a lot of things to change before Mao's death, which makes it harder to speculate. It's a lot like the "what if Trotsky succeeded Lenin?" as a hypothetical - by the time that decision is made, there can be no other outcome. The Cultural Revolution needs to be decisively won by the left factions in order for a plausibly stable chairmanship that isn't either Deng himself or someone very much like him. Once we get there, we probably have to talk about the tensions that were emerging in the coastal factories over central control vs factory democracy and the other left-dissents that emerge during the Hundred Flowers Campaign. Likely you end up with a messy coalition of students and urban workers who don't really agree on anything.