The China during the Cultural Revolution was not a success. Millions were murdered, people starved, and a terrible stain marks that period of China's long history.

It was the pro-capitalist reforms that turned China into the success it is today, and as China starts to falter with it's unmanageable debt and unproductive, government-directed parts of the economy, the reforms will inevitably be capitalist, pro-market solutions that remove the state and promote competition.

So yes, some economies can succeed despite their socialist, government-controlled economic policies, but when things start to fail, solutions all point to the markets.