The stories are a series of logic puzzles. One of the points was that applying broad, simple rules, does not mean the problem is simple. Note, in the stories, the majority of robots are not considered so useless/dangerous to remove positronic robots from the fictional future society (I read a lot of the stories).
> There does not exist a set of rules that make a completely safe and useful robot.
That was not demonstrated. We have safe and useful robots, for some values of 'safe' and 'useful', today. Again, most of the robots in the stories are not thrown (or planned to be thrown) in the metaphorical trash heap.
> There does not exist a set of rules that make a completely safe and useful robot.
That was not demonstrated. We have safe and useful robots, for some values of 'safe' and 'useful', today. Again, most of the robots in the stories are not thrown (or planned to be thrown) in the metaphorical trash heap.