Was the game Ökolopoly an influence on him? It was a 'cybernetic environment game (kybernetik unweltspiel)' from West Germany where players run a country and strive to hold off economic, social and ecological collapse. It was released as a board game (beautiful, if I may so so, owning a copy) in the early 1980s and then the true, apparently fully realised DOS videogame followed later. It always seemed like a simple Sim City to me.

https://de.wikipedia.org/wiki/%C3%96kolopoly

https://archive.org/details/oekolopoly_202509

Further question, how much did he read about cyberneticş beyond Gaia Theory? Was he influenced by Norbert Wiener?