I get your point, but I think your initial conclusions are false. Each of those professions understands that the probability of risk is not 1. Their experience

I get your point, but I think your initial conclusions are false. Each of those professions understands that the probability of risk is not 1. Their experience informs them that the risk is quite unlikely and therefore acceptable. They may have a heightened awareness to look for problems, but they don't stop exposing themselves to risk. Your final conclusion is half-right: ignorance is bliss. But I think it's charitable to say everything is running on goodwill and duct tape. How many people really build systems based on goodwill? And duct tape implies somebody's seen the cracks and decided to patch them. I think everything is running on apathy and incompetence, sitting on the edge of a cliff, waiting for a stiff breeze; over time, the wind wins.