Maybe a single, superintelligent civilization has indeed taken over the galaxy and has imposed strict radio silence because it's paranoid of any potential competitors.
A superintelligent AI is by definition very good at attaining its goals, so the most important thing for us to do is to ensure that its goals are aligned with ours.
The deeper problem is that building superintelligent AI on its own seems likely to be easier than building superintelligent AI and having the completed neuroscience that allows us to seamlessly integrate our minds with it.