"viable" is a relative term though, as is "work." Planned economies don't work, period. Many of the reasons why they don't work applies in full to a cybernetic management scheme up to and possibly including a Culture Mind. (I say possibly, because Culture Minds run on author fiat and may actually be gods) The main one being information gathering which is free and difficult to corrupt in a market economy, while extremely expensive and inherently corrupt in a planned economy. Garbage in, Garbage out, and a planned economy would find it nearly impossible to keep the garbage from coming in.
The easiest way to make it viable is for disaster to strike the West, devastating them enough to make this cybernetically planned system viable, at least for a while. Then again, the soviets would need to steal Western computer technology so...