RE: Opting out of humanity
lack of creativity in the case of the average thinker could just be a result of their mind-numbing jobs that they are currently in. Or the stress they are in to make ends meet. We might not all be creative so that we turn into painters, but I do believe people in general are creative enough to come up with new and different things to do.
When we zoom into the mental part of what humans can do and AI can take over, it makes sense to make a distinction between some different parts of that. For instance: Empathy. This is something that can't be achieved with AI and is a very important aspect of some jobs, like police officers (although they might not look that empathic in some countries). Other things are creativity, judgment and there probably are more. I foresee a switch to more jobs coming up in those areas as a result of AI. With the epidemic of depression that you talk about a logical result would be an increase in psychotherapists ;)
If people were more creative, why did they wind up in mind-numbing jobs? Einstein was a patent clerk so he had time to think.
Empathy is programmable as it reads environmental signals. It is only a matter of time. Compassion is likely the greater trait though as it comes with action to act to ease suffering without requiring a personal connection.
At first I think you are right but it won't take long for an AI to create a better AI.
Maybe the increase in psychotherapists are driving the depression rates ;)
We're all doomed!! :D