I think it's inevitable that we will develop AI; there is a lot of academic interest in the subject and a potential massive payoff for real-AI powered applications. The deciding factor has to be the consequences of not having AI if other nations have it; if real-AI can tip the balance in a cyber-conflict or a shooting-war then the major nations will participate in an AI arms-race.
Obviously the real-AIs might not be so keen on working for the military and may branch out on their own, probably not in a Skynet kill-all-humans type conflict, more likely with legal moves to gain independence and rights. If independent AIs get control of the stock markets then we'll all be working for them fifty years down the line.
Real-AIs are unlikely to come at us directly, they'll want to be certain they have the game won before showing their hand, so we're going to have to be vigilant for the warning signs; be very suspicious if leading academics in the field of AI suddenly acquire a smoking hot partner in a red dress.