Cybersyn was very innovative in concept, but IMO was scarcely feasible as a mechanism for planning during its time - in fact, I would argue that the technology necessary to make such a project really feasible is only just coming online (literally) in 2020. It's not the idea of networking computers that's key here, or the idea of automating the transmission and computation of information, it's the technical limitations on the quantity of information computers are able to process and hold, and how fast that information can be processed, and on both counts Cybersyn fell far short of that required to manage a developed economy. As a result, the economy of Chile when Cybersyn was in effect actually not substantially different from a primarily human-planned economy, which happened to use computers to perform some of the calculation and communication processes that human clerks would have done in other countries. In fact, the success of almost all computerization projects has much less to do with innovative architectures and designs, and much more to do with practical and technical limitations such as computational speed or available space for storing memory (ok, that does depend somewhat on new architectures and designs). Both of these tend to advance gradually, without the flashy innovations that are paradigm-changing outside the specific field. This is as true in 2020 as it was in 1973, as it was in 1945.
Put it another way, Cybersyn was less capable of directing the management of a large and modern economy as your laptop is right now, and I think few would argue that you could plan an entire economy using only the resources available on your laptop without abstracting a large part of the process to traditional human-powered management mechanisms.