China's economy developed under a multi-person single-party system. That has devolved into a dictatorship. I would be cautious about using the last thirty years as a baseline for the next fifty.
Care to elaborate? (full disclosure: I was born and raised in SU and lived in it for 20 years of my life and then another 20 in Russia after the fall). My family were "dissidents", we were under almost constant surveillance since at least 1980 (when I went to the 5th grade) and I can tell that the grip weakened every year until Andropov, who tried to hysterically tighten it, but it didn't work already.
In my simplified opinion, it was just the oil price that killed the Soviet Union. It went from $120 in 1980 to $23 in 1986. Soviet Union as any sufficiently developed socialist economy became more and more dependent on the external supply of goods for which it had to get some hard currency. It basically just run out of money and went bankrupt.