Systems theory is the rebrand of cybernetics IMHO. Cybernetics got diluted as a concept sure to its association with technology and scifi - AI, the Internet, and cyberpunk fiction devices like cyborgs and implants grew out of it and the original ideas got forgotten because they are more difficult to learn, being a very different (as in in addition, not in negation) perspective to the odd mix of scientific materialism and cartesian dualism we have in the West.