Do you have any serious counter arguments to ideas presented in a Bostrom's book? Majority of top AI experts agree that we will have human-level AI by the end of this century, and people like Musk, Bostrom and MIRI guys are just trying to think about possible negative impacts that this development may have on humans. The problem is that the fate of humanity may depend on action of non-human actors, who will likely have utility function incompatible with human survival and it is perfectly rational to be worried about that.

Those ideas are definitely not above criticism but also should not be dismissed based on perceived lack of expertise. Someone like Elon Musk has actually direct contact with people who are working on one of the most advanced AI projects on earth (Vicarious, DeepMind), so he certainly knows what he is talking about.