I have little doubt that humanity will not survive the AI and Robotics revolution very long. If you just synthesize a few of the achievements already gained in AI and robotics, you already have the seeds for our surpassing and end.
1. The other day it was reported that in 4 hours, Deep Mind figured out how to defeat a version of the top chess program that was just a few years old, under rules requiring a move per minute throughout the game. It supposedly did so with no knowledge whatsoever of the history of chess, but only by playing itself many times and learning from what worked and what did not.
Lest you forget, the best humans have been unable to contend with the best software for over 20 years now. AI will eventually surpass human intelligence in all areas by an extraordinary amount, and of course with an enormous but calculable advantage in speed.
2. Robots physically can handle many human tasks already, although typically each robot does relatively limited types of tasks.
They can be constructed to be far stronger, faster, and less vulnerable to attack.
3. The combination of AI and Robotics, then, would be hard to beat, but:
4. Simple control of the Internet and hacking into anything (especially with quantum computing) would allow the AI to control the power system as well as nuclear launch capability. They could launch nukes at the drop of a hat, and then not worry about irradiated food and water.
5. 3-D printing in its future iterations, which would be rapidly improved by an AI system, would allow it to make anything it needed for physical assaults quickly.
6. Any range of possibilities could allow for the release of anti-human AI, as we can see with all the uncontrollable bad actors sending out millions of attacks and numerous viruses against institutional systems on a daily basis.