did they? Not according to 'Marxism'. [Will the real Marxism please stand up.]
A mode of production was defined by Karl Marx by the class relations. The relations between those who controlled the means of production, and those who are producers.
So in feudal society, the Kings and the Lords etc, were basically a Mafia system. They went round to the peasants saying, give us some of your food, and we will protect you. The peasants said who from, and the Lord said, well me for a start.
Over time this became ingrained by custom and religion. However, great swathes of the means of production, the land came to be owned by the church. The Kings and the Lords controlled the land individually, the church bureaucracy collectively. However, the mode of production whether taking place under the control of the church, or under the control of the Kings and the Lords, was the same mode of production, feudalism.
Likewise, in capitalism , the non-Soviet bloc countries, the means of production were controled by individuals, in the Soviet bloc countries, the means of production were controlled by a bureaucracy, but in both cases the class relations remained the same, it remained capitalism, surplus value was still extracted from the producers.
The economy didn't even exist in isolation, in the Soviet bloc countries. It was still tied into the global capitalist economic system, by its military competition. In order to compete with the economies of the West ability to produce weapons of mass destruction, the Soviet bloc countries bureaucracy had to extract more and more surplus value.