I toured East Germany before the wall went down and shortly afterwards
My wife is South African but her family came from East Germany (her dad fled East Germany shortly before the wall went up). The Soviet military infrastructure in East Germany was amazing. The place was an armed camp primed and ready for invasion. It never happened because of the threat of Mutually Assured Destruction (MAD). The Soviet military planners could not come up with a viable invasion strategy (there wasn't one). The only long term strategy they had was to demoralize the West Germans into surrender, i.e. the Green Party. It didn't happen quick enough. So this huge military machine just sat in East Germany with its engine in idle, burning up Soviet resources. Eventually they ran out of gas and the empire imploded.
Gary