We won't be completely obsolete if we learn to modify ourselves. Maybe we get AI to re-design our DNA to be as perfect as possible, to the point we're 1000x smarter than we currently are, and we could design nanobots and/or brain-computer interfaces which allow us to access remote computing power, or even tap into eachothers brains and become a hive mind. AI could just be an extention of ourselves vs a separate entity.