That was true until Xi Jinping removed term limits and ran his corruption campaign that imprisoned and beheaded his competition.

It looks like you don't understand how one party systems work. Just look at Trump and GOP and consider this is a democracy. Once he got the power the whole party(with few exceptions/undesirables that would be eliminated if it were a one party system) got behind him regardless if they liked him or his policies. There was bone to chew and they didn't want to loose it.

If things go south there are plenty to blame(i.e China, Russia, EU, rebels, etc). It is never the leader to blame. As the party leader controlls the police and the millitary there are really very few that would dare to consider a coup/leader change.

Even North Korea's Kim is "officially" supported by his party members but we already know what happens when they question him.