Very sad to see Amit leave; wonderful man and leader. John taking over Search Engine makes perfect sense since AI is predominantly about information, scanning the net and absorbing info like a sponge to make predictive analysis and decisions from the information available to it. Plus, you add the capabilities to assess people’s search and net activities to the mix; AI is about predicting a person’s mind and habits/ interests. So, merging AI and Search totally make sense and probably was already happening anyway given other press releases.
With Amit Singhal leaving, Google is reportedly merging the AI and search divisions.