On your specific point, humans take decades to (very roughly) copy themselves. An AI could do it in minutes with far more precision and control.

Assuming you have 200 IQ, if you could make thousands or millions of clones of yourself quite cheaply, you still might not succeed in taking over the world, but it is no longer a laughable idea.

Overall, I’m somewhat ambivalent about the possibility of x-risk, especially if we work reasonably hard to prevent it.

But it shouldn’t be ignored. AI is moving very quickly and it is unclear how powerful its capabilities will be in the next 10-20 years. Of course, there are many other risks presented by AI that we need to stay on top of as well.