What you describe would be disaster on the global scale and would devastate the economies of the rest of the world. The eastern bloc would probably be less affected that the "free world", but this would be balanced by their economy being more fragile, which in turn would be balanced by their economy being more in the control of the government...
My prediction of what would happen is that everyone would go to damage control mode and economies would globally move towards centrally planned solutions until situation stabilizes. This would be a net win for the eastern bloc elites, they would have a temporary justification for their system and for a temporary rationing of any necessary strictness. This would probably delay the collapse by some unknowable time.
The reason the collapse was so fast was because the people had something better to move to. Under a global economic meltdown caused by the removal of the US, there would be no real immediate benefit from breaking the eastern bloc and even with the nothing else changing, the process would be slower. Which would probably be a good thing, the fast process that actually happened had some issues that might be avoided with less pressure to move fast.
Since the destruction of the US and a global economic meltdown would also end the cold war for the duration without anyone having to lose face, this would also open the window for the Soviet leadership to go for reform lot more aggressively than was possible in actual history. Almost any reform could be justified as emergency response to the situation and implemented by force if necessary. People would also be more motivated to work together. Even cooperation across the iron curtain would now be possible. It is debatable whether the soviet leadership would have the ability to pursue this possibility though, but you can even build a scenario where the eastern bloc survives in reformed form.
Alternate outcome is the eastern bloc using the military window instead. Loss of the US would devastate the west militarily and turn the power of balance in the favor of the Soviets. The soviet leadership might decide to use the opening and invade the western europe. This would give them the resources and strategic position to prop up their power even without successful reform.
And of course, integrating the western Europe would open its own window for reforming the system. Just treat the Europeans softly, and instead of forcing all the ineffciencies of the soviet system of them, use them as model for reforms in the east.
So maybe the answer would be, possibly not, if the soviet leadership responds decisively and effciently. Otherwise, the process would be slower. Unless the soviets mess up their response, in which case it would be faster... (Not very useful answer, is it?)