We can't know exactly what will happen, but we can make informed speculation. Bostrom studied many different scenarios for the future of AI, and the arguments f

We can't know exactly what will happen, but we can make informed speculation. Bostrom studied many different scenarios for the future of AI, and the arguments for and against them. He's even contributed to AI safety research, the study of methods to control future intelligent algorithms. So yes he absolutely is more informed than a psychic, or even an expert in today's machine learning. And he isn't even making very specific predictions. He's not giving an exact timetable of when we will have AI, or what algorithms it will use. Just a very general prediction that we will get superintelligence someday, and that it will be very dangerous if we don't solve the control problem. These seem like very reasonable statements, and have strong arguments for them IMO.