Out of curiosity, what does quantum computing has to do with it?Maybe advancements in neuroscience will outpace advancements in artificial intelligence.
We could master our own consciousness and intelligence to the point that machine intelligence becomes redundant. E.g.:
1) We manipulate the brain to master our own happiness. For example we could exist in a permanent dream-state, an sort of internal simulation, stimulated in such a way to create as close to a perfect "existence" as possible. This might seem far-fetched at the moment, but we're only just scratching the surface of biological sleep - the power it has for us, and the control we can exert over it. This would probably involve some machine technology, but not necessarily AI.
2) We "artificially evolve" our minds to become ever more rational and logical. We could end up rationalising even our own existence, overriding our most fundamental instincts - to survive and procreate.
Both scenarios ultimately lead to a gradual slide into peaceful human extinction rather than what could be perceived as the never-ending futility of species survival.
Even if those don't happen, I wouldn't be surprised if artificial intelligence comes in a more biological form - a "grown" intelligence or superorganism rather than a machine intelligence. But I might be overlooking quantum computing.
From what I know, despite that our brain is a quantum system (same as everything else in the universe), experts seem to believe that quantum mechanics plays no role in intelligence and conscience. Also, most experts seem to think that the main thing we would get from quantum computing is that we will be able to directly simulate quantum systems there, not that it will create more powerful supercomputers.
I know that there is quantum machine learning, but ai have to talk with anyone who thinks that will be a big thing in the near to mid future. Even if quantum computing becomes a thing, it is very hard to see it being useful for machine learning (unlike for example, for cryptography where quantum computing will be a dealbreaker).